GNU Linux-libre 5.19-rc6-gnu
[releases.git] / fs / pstore / platform.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Persistent Storage - platform driver interface parts.
4  *
5  * Copyright (C) 2007-2008 Google, Inc.
6  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
7  */
8
9 #define pr_fmt(fmt) "pstore: " fmt
10
11 #include <linux/atomic.h>
12 #include <linux/types.h>
13 #include <linux/errno.h>
14 #include <linux/init.h>
15 #include <linux/kmsg_dump.h>
16 #include <linux/console.h>
17 #include <linux/module.h>
18 #include <linux/pstore.h>
19 #if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
20 #include <linux/lzo.h>
21 #endif
22 #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
23 #include <linux/lz4.h>
24 #endif
25 #if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
26 #include <linux/zstd.h>
27 #endif
28 #include <linux/crypto.h>
29 #include <linux/string.h>
30 #include <linux/timer.h>
31 #include <linux/slab.h>
32 #include <linux/uaccess.h>
33 #include <linux/jiffies.h>
34 #include <linux/workqueue.h>
35
36 #include "internal.h"
37
38 /*
39  * We defer making "oops" entries appear in pstore - see
40  * whether the system is actually still running well enough
41  * to let someone see the entry
42  */
43 static int pstore_update_ms = -1;
44 module_param_named(update_ms, pstore_update_ms, int, 0600);
45 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
46                  "(default is -1, which means runtime updates are disabled; "
47                  "enabling this option may not be safe; it may lead to further "
48                  "corruption on Oopses)");
49
50 /* Names should be in the same order as the enum pstore_type_id */
51 static const char * const pstore_type_names[] = {
52         "dmesg",
53         "mce",
54         "console",
55         "ftrace",
56         "rtas",
57         "powerpc-ofw",
58         "powerpc-common",
59         "pmsg",
60         "powerpc-opal",
61 };
62
63 static int pstore_new_entry;
64
65 static void pstore_timefunc(struct timer_list *);
66 static DEFINE_TIMER(pstore_timer, pstore_timefunc);
67
68 static void pstore_dowork(struct work_struct *);
69 static DECLARE_WORK(pstore_work, pstore_dowork);
70
71 /*
72  * psinfo_lock protects "psinfo" during calls to
73  * pstore_register(), pstore_unregister(), and
74  * the filesystem mount/unmount routines.
75  */
76 static DEFINE_MUTEX(psinfo_lock);
77 struct pstore_info *psinfo;
78
79 static char *backend;
80 module_param(backend, charp, 0444);
81 MODULE_PARM_DESC(backend, "specific backend to use");
82
83 static char *compress =
84 #ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
85                 CONFIG_PSTORE_COMPRESS_DEFAULT;
86 #else
87                 NULL;
88 #endif
89 module_param(compress, charp, 0444);
90 MODULE_PARM_DESC(compress, "compression to use");
91
92 /* Compression parameters */
93 static struct crypto_comp *tfm;
94
95 struct pstore_zbackend {
96         int (*zbufsize)(size_t size);
97         const char *name;
98 };
99
100 static char *big_oops_buf;
101 static size_t big_oops_buf_sz;
102
103 /* How much of the console log to snapshot */
104 unsigned long kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES;
105
106 void pstore_set_kmsg_bytes(int bytes)
107 {
108         kmsg_bytes = bytes;
109 }
110
111 /* Tag each group of saved records with a sequence number */
112 static int      oopscount;
113
114 const char *pstore_type_to_name(enum pstore_type_id type)
115 {
116         BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
117
118         if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
119                 return "unknown";
120
121         return pstore_type_names[type];
122 }
123 EXPORT_SYMBOL_GPL(pstore_type_to_name);
124
125 enum pstore_type_id pstore_name_to_type(const char *name)
126 {
127         int i;
128
129         for (i = 0; i < PSTORE_TYPE_MAX; i++) {
130                 if (!strcmp(pstore_type_names[i], name))
131                         return i;
132         }
133
134         return PSTORE_TYPE_MAX;
135 }
136 EXPORT_SYMBOL_GPL(pstore_name_to_type);
137
138 static void pstore_timer_kick(void)
139 {
140         if (pstore_update_ms < 0)
141                 return;
142
143         mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
144 }
145
146 static bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
147 {
148         /*
149          * In case of NMI path, pstore shouldn't be blocked
150          * regardless of reason.
151          */
152         if (in_nmi())
153                 return true;
154
155         switch (reason) {
156         /* In panic case, other cpus are stopped by smp_send_stop(). */
157         case KMSG_DUMP_PANIC:
158         /*
159          * Emergency restart shouldn't be blocked by spinning on
160          * pstore_info::buf_lock.
161          */
162         case KMSG_DUMP_EMERG:
163                 return true;
164         default:
165                 return false;
166         }
167 }
168
169 #if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
170 static int zbufsize_deflate(size_t size)
171 {
172         size_t cmpr;
173
174         switch (size) {
175         /* buffer range for efivars */
176         case 1000 ... 2000:
177                 cmpr = 56;
178                 break;
179         case 2001 ... 3000:
180                 cmpr = 54;
181                 break;
182         case 3001 ... 3999:
183                 cmpr = 52;
184                 break;
185         /* buffer range for nvram, erst */
186         case 4000 ... 10000:
187                 cmpr = 45;
188                 break;
189         default:
190                 cmpr = 60;
191                 break;
192         }
193
194         return (size * 100) / cmpr;
195 }
196 #endif
197
198 #if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
199 static int zbufsize_lzo(size_t size)
200 {
201         return lzo1x_worst_compress(size);
202 }
203 #endif
204
205 #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
206 static int zbufsize_lz4(size_t size)
207 {
208         return LZ4_compressBound(size);
209 }
210 #endif
211
212 #if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
213 static int zbufsize_842(size_t size)
214 {
215         return size;
216 }
217 #endif
218
219 #if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
220 static int zbufsize_zstd(size_t size)
221 {
222         return zstd_compress_bound(size);
223 }
224 #endif
225
226 static const struct pstore_zbackend *zbackend __ro_after_init;
227
228 static const struct pstore_zbackend zbackends[] = {
229 #if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
230         {
231                 .zbufsize       = zbufsize_deflate,
232                 .name           = "deflate",
233         },
234 #endif
235 #if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
236         {
237                 .zbufsize       = zbufsize_lzo,
238                 .name           = "lzo",
239         },
240 #endif
241 #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS)
242         {
243                 .zbufsize       = zbufsize_lz4,
244                 .name           = "lz4",
245         },
246 #endif
247 #if IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
248         {
249                 .zbufsize       = zbufsize_lz4,
250                 .name           = "lz4hc",
251         },
252 #endif
253 #if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
254         {
255                 .zbufsize       = zbufsize_842,
256                 .name           = "842",
257         },
258 #endif
259 #if IS_ENABLED(CONFIG_PSTORE_ZSTD_COMPRESS)
260         {
261                 .zbufsize       = zbufsize_zstd,
262                 .name           = "zstd",
263         },
264 #endif
265         { }
266 };
267
268 static int pstore_compress(const void *in, void *out,
269                            unsigned int inlen, unsigned int outlen)
270 {
271         int ret;
272
273         if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS))
274                 return -EINVAL;
275
276         ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
277         if (ret) {
278                 pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
279                 return ret;
280         }
281
282         return outlen;
283 }
284
285 static void allocate_buf_for_compression(void)
286 {
287         struct crypto_comp *ctx;
288         int size;
289         char *buf;
290
291         /* Skip if not built-in or compression backend not selected yet. */
292         if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
293                 return;
294
295         /* Skip if no pstore backend yet or compression init already done. */
296         if (!psinfo || tfm)
297                 return;
298
299         if (!crypto_has_comp(zbackend->name, 0, 0)) {
300                 pr_err("Unknown compression: %s\n", zbackend->name);
301                 return;
302         }
303
304         size = zbackend->zbufsize(psinfo->bufsize);
305         if (size <= 0) {
306                 pr_err("Invalid compression size for %s: %d\n",
307                        zbackend->name, size);
308                 return;
309         }
310
311         buf = kmalloc(size, GFP_KERNEL);
312         if (!buf) {
313                 pr_err("Failed %d byte compression buffer allocation for: %s\n",
314                        size, zbackend->name);
315                 return;
316         }
317
318         ctx = crypto_alloc_comp(zbackend->name, 0, 0);
319         if (IS_ERR_OR_NULL(ctx)) {
320                 kfree(buf);
321                 pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
322                        PTR_ERR(ctx));
323                 return;
324         }
325
326         /* A non-NULL big_oops_buf indicates compression is available. */
327         tfm = ctx;
328         big_oops_buf_sz = size;
329         big_oops_buf = buf;
330
331         pr_info("Using crash dump compression: %s\n", zbackend->name);
332 }
333
334 static void free_buf_for_compression(void)
335 {
336         if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) {
337                 crypto_free_comp(tfm);
338                 tfm = NULL;
339         }
340         kfree(big_oops_buf);
341         big_oops_buf = NULL;
342         big_oops_buf_sz = 0;
343 }
344
345 /*
346  * Called when compression fails, since the printk buffer
347  * would be fetched for compression calling it again when
348  * compression fails would have moved the iterator of
349  * printk buffer which results in fetching old contents.
350  * Copy the recent messages from big_oops_buf to psinfo->buf
351  */
352 static size_t copy_kmsg_to_buffer(int hsize, size_t len)
353 {
354         size_t total_len;
355         size_t diff;
356
357         total_len = hsize + len;
358
359         if (total_len > psinfo->bufsize) {
360                 diff = total_len - psinfo->bufsize + hsize;
361                 memcpy(psinfo->buf, big_oops_buf, hsize);
362                 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
363                                         psinfo->bufsize - hsize);
364                 total_len = psinfo->bufsize;
365         } else
366                 memcpy(psinfo->buf, big_oops_buf, total_len);
367
368         return total_len;
369 }
370
371 void pstore_record_init(struct pstore_record *record,
372                         struct pstore_info *psinfo)
373 {
374         memset(record, 0, sizeof(*record));
375
376         record->psi = psinfo;
377
378         /* Report zeroed timestamp if called before timekeeping has resumed. */
379         record->time = ns_to_timespec64(ktime_get_real_fast_ns());
380 }
381
382 /*
383  * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
384  * end of the buffer.
385  */
386 static void pstore_dump(struct kmsg_dumper *dumper,
387                         enum kmsg_dump_reason reason)
388 {
389         struct kmsg_dump_iter iter;
390         unsigned long   total = 0;
391         const char      *why;
392         unsigned int    part = 1;
393         unsigned long   flags = 0;
394         int             ret;
395
396         why = kmsg_dump_reason_str(reason);
397
398         if (pstore_cannot_block_path(reason)) {
399                 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
400                         pr_err("dump skipped in %s path because of concurrent dump\n",
401                                         in_nmi() ? "NMI" : why);
402                         return;
403                 }
404         } else {
405                 spin_lock_irqsave(&psinfo->buf_lock, flags);
406         }
407
408         kmsg_dump_rewind(&iter);
409
410         oopscount++;
411         while (total < kmsg_bytes) {
412                 char *dst;
413                 size_t dst_size;
414                 int header_size;
415                 int zipped_len = -1;
416                 size_t dump_size;
417                 struct pstore_record record;
418
419                 pstore_record_init(&record, psinfo);
420                 record.type = PSTORE_TYPE_DMESG;
421                 record.count = oopscount;
422                 record.reason = reason;
423                 record.part = part;
424                 record.buf = psinfo->buf;
425
426                 if (big_oops_buf) {
427                         dst = big_oops_buf;
428                         dst_size = big_oops_buf_sz;
429                 } else {
430                         dst = psinfo->buf;
431                         dst_size = psinfo->bufsize;
432                 }
433
434                 /* Write dump header. */
435                 header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
436                                  oopscount, part);
437                 dst_size -= header_size;
438
439                 /* Write dump contents. */
440                 if (!kmsg_dump_get_buffer(&iter, true, dst + header_size,
441                                           dst_size, &dump_size))
442                         break;
443
444                 if (big_oops_buf) {
445                         zipped_len = pstore_compress(dst, psinfo->buf,
446                                                 header_size + dump_size,
447                                                 psinfo->bufsize);
448
449                         if (zipped_len > 0) {
450                                 record.compressed = true;
451                                 record.size = zipped_len;
452                         } else {
453                                 record.size = copy_kmsg_to_buffer(header_size,
454                                                                   dump_size);
455                         }
456                 } else {
457                         record.size = header_size + dump_size;
458                 }
459
460                 ret = psinfo->write(&record);
461                 if (ret == 0 && reason == KMSG_DUMP_OOPS) {
462                         pstore_new_entry = 1;
463                         pstore_timer_kick();
464                 }
465
466                 total += record.size;
467                 part++;
468         }
469         spin_unlock_irqrestore(&psinfo->buf_lock, flags);
470 }
471
472 static struct kmsg_dumper pstore_dumper = {
473         .dump = pstore_dump,
474 };
475
476 /*
477  * Register with kmsg_dump to save last part of console log on panic.
478  */
479 static void pstore_register_kmsg(void)
480 {
481         kmsg_dump_register(&pstore_dumper);
482 }
483
484 static void pstore_unregister_kmsg(void)
485 {
486         kmsg_dump_unregister(&pstore_dumper);
487 }
488
489 #ifdef CONFIG_PSTORE_CONSOLE
490 static void pstore_console_write(struct console *con, const char *s, unsigned c)
491 {
492         struct pstore_record record;
493
494         if (!c)
495                 return;
496
497         pstore_record_init(&record, psinfo);
498         record.type = PSTORE_TYPE_CONSOLE;
499
500         record.buf = (char *)s;
501         record.size = c;
502         psinfo->write(&record);
503 }
504
505 static struct console pstore_console = {
506         .write  = pstore_console_write,
507         .index  = -1,
508 };
509
510 static void pstore_register_console(void)
511 {
512         /* Show which backend is going to get console writes. */
513         strscpy(pstore_console.name, psinfo->name,
514                 sizeof(pstore_console.name));
515         /*
516          * Always initialize flags here since prior unregister_console()
517          * calls may have changed settings (specifically CON_ENABLED).
518          */
519         pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
520         register_console(&pstore_console);
521 }
522
523 static void pstore_unregister_console(void)
524 {
525         unregister_console(&pstore_console);
526 }
527 #else
528 static void pstore_register_console(void) {}
529 static void pstore_unregister_console(void) {}
530 #endif
531
532 static int pstore_write_user_compat(struct pstore_record *record,
533                                     const char __user *buf)
534 {
535         int ret = 0;
536
537         if (record->buf)
538                 return -EINVAL;
539
540         record->buf = memdup_user(buf, record->size);
541         if (IS_ERR(record->buf)) {
542                 ret = PTR_ERR(record->buf);
543                 goto out;
544         }
545
546         ret = record->psi->write(record);
547
548         kfree(record->buf);
549 out:
550         record->buf = NULL;
551
552         return unlikely(ret < 0) ? ret : record->size;
553 }
554
555 /*
556  * platform specific persistent storage driver registers with
557  * us here. If pstore is already mounted, call the platform
558  * read function right away to populate the file system. If not
559  * then the pstore mount code will call us later to fill out
560  * the file system.
561  */
562 int pstore_register(struct pstore_info *psi)
563 {
564         if (backend && strcmp(backend, psi->name)) {
565                 pr_warn("ignoring unexpected backend '%s'\n", psi->name);
566                 return -EPERM;
567         }
568
569         /* Sanity check flags. */
570         if (!psi->flags) {
571                 pr_warn("backend '%s' must support at least one frontend\n",
572                         psi->name);
573                 return -EINVAL;
574         }
575
576         /* Check for required functions. */
577         if (!psi->read || !psi->write) {
578                 pr_warn("backend '%s' must implement read() and write()\n",
579                         psi->name);
580                 return -EINVAL;
581         }
582
583         mutex_lock(&psinfo_lock);
584         if (psinfo) {
585                 pr_warn("backend '%s' already loaded: ignoring '%s'\n",
586                         psinfo->name, psi->name);
587                 mutex_unlock(&psinfo_lock);
588                 return -EBUSY;
589         }
590
591         if (!psi->write_user)
592                 psi->write_user = pstore_write_user_compat;
593         psinfo = psi;
594         mutex_init(&psinfo->read_mutex);
595         spin_lock_init(&psinfo->buf_lock);
596
597         if (psi->flags & PSTORE_FLAGS_DMESG)
598                 allocate_buf_for_compression();
599
600         pstore_get_records(0);
601
602         if (psi->flags & PSTORE_FLAGS_DMESG) {
603                 pstore_dumper.max_reason = psinfo->max_reason;
604                 pstore_register_kmsg();
605         }
606         if (psi->flags & PSTORE_FLAGS_CONSOLE)
607                 pstore_register_console();
608         if (psi->flags & PSTORE_FLAGS_FTRACE)
609                 pstore_register_ftrace();
610         if (psi->flags & PSTORE_FLAGS_PMSG)
611                 pstore_register_pmsg();
612
613         /* Start watching for new records, if desired. */
614         pstore_timer_kick();
615
616         /*
617          * Update the module parameter backend, so it is visible
618          * through /sys/module/pstore/parameters/backend
619          */
620         backend = kstrdup(psi->name, GFP_KERNEL);
621
622         pr_info("Registered %s as persistent store backend\n", psi->name);
623
624         mutex_unlock(&psinfo_lock);
625         return 0;
626 }
627 EXPORT_SYMBOL_GPL(pstore_register);
628
629 void pstore_unregister(struct pstore_info *psi)
630 {
631         /* It's okay to unregister nothing. */
632         if (!psi)
633                 return;
634
635         mutex_lock(&psinfo_lock);
636
637         /* Only one backend can be registered at a time. */
638         if (WARN_ON(psi != psinfo)) {
639                 mutex_unlock(&psinfo_lock);
640                 return;
641         }
642
643         /* Unregister all callbacks. */
644         if (psi->flags & PSTORE_FLAGS_PMSG)
645                 pstore_unregister_pmsg();
646         if (psi->flags & PSTORE_FLAGS_FTRACE)
647                 pstore_unregister_ftrace();
648         if (psi->flags & PSTORE_FLAGS_CONSOLE)
649                 pstore_unregister_console();
650         if (psi->flags & PSTORE_FLAGS_DMESG)
651                 pstore_unregister_kmsg();
652
653         /* Stop timer and make sure all work has finished. */
654         del_timer_sync(&pstore_timer);
655         flush_work(&pstore_work);
656
657         /* Remove all backend records from filesystem tree. */
658         pstore_put_backend_records(psi);
659
660         free_buf_for_compression();
661
662         psinfo = NULL;
663         kfree(backend);
664         backend = NULL;
665         mutex_unlock(&psinfo_lock);
666 }
667 EXPORT_SYMBOL_GPL(pstore_unregister);
668
669 static void decompress_record(struct pstore_record *record)
670 {
671         int ret;
672         int unzipped_len;
673         char *unzipped, *workspace;
674
675         if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
676                 return;
677
678         /* Only PSTORE_TYPE_DMESG support compression. */
679         if (record->type != PSTORE_TYPE_DMESG) {
680                 pr_warn("ignored compressed record type %d\n", record->type);
681                 return;
682         }
683
684         /* Missing compression buffer means compression was not initialized. */
685         if (!big_oops_buf) {
686                 pr_warn("no decompression method initialized!\n");
687                 return;
688         }
689
690         /* Allocate enough space to hold max decompression and ECC. */
691         unzipped_len = big_oops_buf_sz;
692         workspace = kmalloc(unzipped_len + record->ecc_notice_size,
693                             GFP_KERNEL);
694         if (!workspace)
695                 return;
696
697         /* After decompression "unzipped_len" is almost certainly smaller. */
698         ret = crypto_comp_decompress(tfm, record->buf, record->size,
699                                           workspace, &unzipped_len);
700         if (ret) {
701                 pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
702                 kfree(workspace);
703                 return;
704         }
705
706         /* Append ECC notice to decompressed buffer. */
707         memcpy(workspace + unzipped_len, record->buf + record->size,
708                record->ecc_notice_size);
709
710         /* Copy decompressed contents into an minimum-sized allocation. */
711         unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
712                            GFP_KERNEL);
713         kfree(workspace);
714         if (!unzipped)
715                 return;
716
717         /* Swap out compressed contents with decompressed contents. */
718         kfree(record->buf);
719         record->buf = unzipped;
720         record->size = unzipped_len;
721         record->compressed = false;
722 }
723
724 /*
725  * Read all the records from one persistent store backend. Create
726  * files in our filesystem.  Don't warn about -EEXIST errors
727  * when we are re-scanning the backing store looking to add new
728  * error records.
729  */
730 void pstore_get_backend_records(struct pstore_info *psi,
731                                 struct dentry *root, int quiet)
732 {
733         int failed = 0;
734         unsigned int stop_loop = 65536;
735
736         if (!psi || !root)
737                 return;
738
739         mutex_lock(&psi->read_mutex);
740         if (psi->open && psi->open(psi))
741                 goto out;
742
743         /*
744          * Backend callback read() allocates record.buf. decompress_record()
745          * may reallocate record.buf. On success, pstore_mkfile() will keep
746          * the record.buf, so free it only on failure.
747          */
748         for (; stop_loop; stop_loop--) {
749                 struct pstore_record *record;
750                 int rc;
751
752                 record = kzalloc(sizeof(*record), GFP_KERNEL);
753                 if (!record) {
754                         pr_err("out of memory creating record\n");
755                         break;
756                 }
757                 pstore_record_init(record, psi);
758
759                 record->size = psi->read(record);
760
761                 /* No more records left in backend? */
762                 if (record->size <= 0) {
763                         kfree(record);
764                         break;
765                 }
766
767                 decompress_record(record);
768                 rc = pstore_mkfile(root, record);
769                 if (rc) {
770                         /* pstore_mkfile() did not take record, so free it. */
771                         kfree(record->buf);
772                         kfree(record);
773                         if (rc != -EEXIST || !quiet)
774                                 failed++;
775                 }
776         }
777         if (psi->close)
778                 psi->close(psi);
779 out:
780         mutex_unlock(&psi->read_mutex);
781
782         if (failed)
783                 pr_warn("failed to create %d record(s) from '%s'\n",
784                         failed, psi->name);
785         if (!stop_loop)
786                 pr_err("looping? Too many records seen from '%s'\n",
787                         psi->name);
788 }
789
790 static void pstore_dowork(struct work_struct *work)
791 {
792         pstore_get_records(1);
793 }
794
795 static void pstore_timefunc(struct timer_list *unused)
796 {
797         if (pstore_new_entry) {
798                 pstore_new_entry = 0;
799                 schedule_work(&pstore_work);
800         }
801
802         pstore_timer_kick();
803 }
804
805 static void __init pstore_choose_compression(void)
806 {
807         const struct pstore_zbackend *step;
808
809         if (!compress)
810                 return;
811
812         for (step = zbackends; step->name; step++) {
813                 if (!strcmp(compress, step->name)) {
814                         zbackend = step;
815                         return;
816                 }
817         }
818 }
819
820 static int __init pstore_init(void)
821 {
822         int ret;
823
824         pstore_choose_compression();
825
826         /*
827          * Check if any pstore backends registered earlier but did not
828          * initialize compression because crypto was not ready. If so,
829          * initialize compression now.
830          */
831         allocate_buf_for_compression();
832
833         ret = pstore_init_fs();
834         if (ret)
835                 free_buf_for_compression();
836
837         return ret;
838 }
839 late_initcall(pstore_init);
840
841 static void __exit pstore_exit(void)
842 {
843         pstore_exit_fs();
844 }
845 module_exit(pstore_exit)
846
847 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
848 MODULE_LICENSE("GPL");