xref: /linux/fs/pstore/platform.c (revision 42d37fc0c819b81f6f6afd108b55d04ba9d32d0f)
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/mm.h>
18 #include <linux/module.h>
19 #include <linux/pstore.h>
20 #include <linux/string.h>
21 #include <linux/timer.h>
22 #include <linux/slab.h>
23 #include <linux/uaccess.h>
24 #include <linux/jiffies.h>
25 #include <linux/vmalloc.h>
26 #include <linux/workqueue.h>
27 #include <linux/zlib.h>
28 
29 #include "internal.h"
30 
31 /*
32  * We defer making "oops" entries appear in pstore - see
33  * whether the system is actually still running well enough
34  * to let someone see the entry
35  */
36 static int pstore_update_ms = -1;
37 module_param_named(update_ms, pstore_update_ms, int, 0600);
38 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
39 		 "(default is -1, which means runtime updates are disabled; "
40 		 "enabling this option may not be safe; it may lead to further "
41 		 "corruption on Oopses)");
42 
43 /* Names should be in the same order as the enum pstore_type_id */
44 static const char * const pstore_type_names[] = {
45 	"dmesg",
46 	"mce",
47 	"console",
48 	"ftrace",
49 	"rtas",
50 	"powerpc-ofw",
51 	"powerpc-common",
52 	"pmsg",
53 	"powerpc-opal",
54 };
55 
56 static int pstore_new_entry;
57 
58 static void pstore_timefunc(struct timer_list *);
59 static DEFINE_TIMER(pstore_timer, pstore_timefunc);
60 
61 static void pstore_dowork(struct work_struct *);
62 static DECLARE_WORK(pstore_work, pstore_dowork);
63 
64 /*
65  * psinfo_lock protects "psinfo" during calls to
66  * pstore_register(), pstore_unregister(), and
67  * the filesystem mount/unmount routines.
68  */
69 static DEFINE_MUTEX(psinfo_lock);
70 struct pstore_info *psinfo;
71 
72 static char *backend;
73 module_param(backend, charp, 0444);
74 MODULE_PARM_DESC(backend, "specific backend to use");
75 
76 /*
77  * pstore no longer implements compression via the crypto API, and only
78  * supports zlib deflate compression implemented using the zlib library
79  * interface. This removes additional complexity which is hard to justify for a
80  * diagnostic facility that has to operate in conditions where the system may
81  * have become unstable. Zlib deflate is comparatively small in terms of code
82  * size, and compresses ASCII text comparatively well. In terms of compression
83  * speed, deflate is not the best performer but for recording the log output on
84  * a kernel panic, this is not considered critical.
85  *
86  * The only remaining arguments supported by the compress= module parameter are
87  * 'deflate' and 'none'. To retain compatibility with existing installations,
88  * all other values are logged and replaced with 'deflate'.
89  */
90 static char *compress = "deflate";
91 module_param(compress, charp, 0444);
92 MODULE_PARM_DESC(compress, "compression to use");
93 
94 /* How much of the kernel log to snapshot */
95 unsigned long kmsg_bytes = CONFIG_PSTORE_DEFAULT_KMSG_BYTES;
96 module_param(kmsg_bytes, ulong, 0444);
97 MODULE_PARM_DESC(kmsg_bytes, "amount of kernel log to snapshot (in bytes)");
98 
99 static void *compress_workspace;
100 
101 /*
102  * Compression is only used for dmesg output, which consists of low-entropy
103  * ASCII text, and so we can assume worst-case 60%.
104  */
105 #define DMESG_COMP_PERCENT	60
106 
107 static char *big_oops_buf;
108 static size_t max_compressed_size;
109 
110 void pstore_set_kmsg_bytes(int bytes)
111 {
112 	kmsg_bytes = bytes;
113 }
114 
115 /* Tag each group of saved records with a sequence number */
116 static int	oopscount;
117 
118 const char *pstore_type_to_name(enum pstore_type_id type)
119 {
120 	BUILD_BUG_ON(ARRAY_SIZE(pstore_type_names) != PSTORE_TYPE_MAX);
121 
122 	if (WARN_ON_ONCE(type >= PSTORE_TYPE_MAX))
123 		return "unknown";
124 
125 	return pstore_type_names[type];
126 }
127 EXPORT_SYMBOL_GPL(pstore_type_to_name);
128 
129 enum pstore_type_id pstore_name_to_type(const char *name)
130 {
131 	int i;
132 
133 	for (i = 0; i < PSTORE_TYPE_MAX; i++) {
134 		if (!strcmp(pstore_type_names[i], name))
135 			return i;
136 	}
137 
138 	return PSTORE_TYPE_MAX;
139 }
140 EXPORT_SYMBOL_GPL(pstore_name_to_type);
141 
142 static void pstore_timer_kick(void)
143 {
144 	if (pstore_update_ms < 0)
145 		return;
146 
147 	mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
148 }
149 
150 static bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
151 {
152 	/*
153 	 * In case of NMI path, pstore shouldn't be blocked
154 	 * regardless of reason.
155 	 */
156 	if (in_nmi())
157 		return true;
158 
159 	switch (reason) {
160 	/* In panic case, other cpus are stopped by smp_send_stop(). */
161 	case KMSG_DUMP_PANIC:
162 	/*
163 	 * Emergency restart shouldn't be blocked by spinning on
164 	 * pstore_info::buf_lock.
165 	 */
166 	case KMSG_DUMP_EMERG:
167 		return true;
168 	default:
169 		return false;
170 	}
171 }
172 
173 static int pstore_compress(const void *in, void *out,
174 			   unsigned int inlen, unsigned int outlen)
175 {
176 	struct z_stream_s zstream = {
177 		.next_in	= in,
178 		.avail_in	= inlen,
179 		.next_out	= out,
180 		.avail_out	= outlen,
181 		.workspace	= compress_workspace,
182 	};
183 	int ret;
184 
185 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS))
186 		return -EINVAL;
187 
188 	ret = zlib_deflateInit2(&zstream, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
189 				-MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
190 	if (ret != Z_OK)
191 		return -EINVAL;
192 
193 	ret = zlib_deflate(&zstream, Z_FINISH);
194 	if (ret != Z_STREAM_END)
195 		return -EINVAL;
196 
197 	ret = zlib_deflateEnd(&zstream);
198 	if (ret != Z_OK)
199 		pr_warn_once("zlib_deflateEnd() failed: %d\n", ret);
200 
201 	return zstream.total_out;
202 }
203 
204 static void allocate_buf_for_compression(void)
205 {
206 	size_t compressed_size;
207 	char *buf;
208 
209 	/* Skip if not built-in or compression disabled. */
210 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !compress ||
211 	    !strcmp(compress, "none")) {
212 		compress = NULL;
213 		return;
214 	}
215 
216 	if (strcmp(compress, "deflate")) {
217 		pr_err("Unsupported compression '%s', falling back to deflate\n",
218 		       compress);
219 		compress = "deflate";
220 	}
221 
222 	/*
223 	 * The compression buffer only needs to be as large as the maximum
224 	 * uncompressed record size, since any record that would be expanded by
225 	 * compression is just stored uncompressed.
226 	 */
227 	compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT;
228 	buf = kvzalloc(compressed_size, GFP_KERNEL);
229 	if (!buf) {
230 		pr_err("Failed %zu byte compression buffer allocation for: %s\n",
231 		       psinfo->bufsize, compress);
232 		return;
233 	}
234 
235 	compress_workspace =
236 		vmalloc(zlib_deflate_workspacesize(MAX_WBITS, DEF_MEM_LEVEL));
237 	if (!compress_workspace) {
238 		pr_err("Failed to allocate zlib deflate workspace\n");
239 		kvfree(buf);
240 		return;
241 	}
242 
243 	/* A non-NULL big_oops_buf indicates compression is available. */
244 	big_oops_buf = buf;
245 	max_compressed_size = compressed_size;
246 
247 	pr_info("Using crash dump compression: %s\n", compress);
248 }
249 
250 static void free_buf_for_compression(void)
251 {
252 	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress_workspace) {
253 		vfree(compress_workspace);
254 		compress_workspace = NULL;
255 	}
256 
257 	kvfree(big_oops_buf);
258 	big_oops_buf = NULL;
259 	max_compressed_size = 0;
260 }
261 
262 void pstore_record_init(struct pstore_record *record,
263 			struct pstore_info *psinfo)
264 {
265 	memset(record, 0, sizeof(*record));
266 
267 	record->psi = psinfo;
268 
269 	/* Report zeroed timestamp if called before timekeeping has resumed. */
270 	record->time = ns_to_timespec64(ktime_get_real_fast_ns());
271 }
272 
273 /*
274  * callback from kmsg_dump. Save as much as we can (up to kmsg_bytes) from the
275  * end of the buffer.
276  */
277 static void pstore_dump(struct kmsg_dumper *dumper,
278 			enum kmsg_dump_reason reason)
279 {
280 	struct kmsg_dump_iter iter;
281 	unsigned long	total = 0;
282 	const char	*why;
283 	unsigned int	part = 1;
284 	unsigned long	flags = 0;
285 	int		saved_ret = 0;
286 	int		ret;
287 
288 	why = kmsg_dump_reason_str(reason);
289 
290 	if (pstore_cannot_block_path(reason)) {
291 		if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) {
292 			pr_err("dump skipped in %s path because of concurrent dump\n",
293 					in_nmi() ? "NMI" : why);
294 			return;
295 		}
296 	} else {
297 		spin_lock_irqsave(&psinfo->buf_lock, flags);
298 	}
299 
300 	kmsg_dump_rewind(&iter);
301 
302 	oopscount++;
303 	while (total < kmsg_bytes) {
304 		char *dst;
305 		size_t dst_size;
306 		int header_size;
307 		int zipped_len = -1;
308 		size_t dump_size;
309 		struct pstore_record record;
310 
311 		pstore_record_init(&record, psinfo);
312 		record.type = PSTORE_TYPE_DMESG;
313 		record.count = oopscount;
314 		record.reason = reason;
315 		record.part = part;
316 		record.buf = psinfo->buf;
317 
318 		dst = big_oops_buf ?: psinfo->buf;
319 		dst_size = max_compressed_size ?: psinfo->bufsize;
320 
321 		/* Write dump header. */
322 		header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
323 				 oopscount, part);
324 		dst_size -= header_size;
325 
326 		/* Write dump contents. */
327 		if (!kmsg_dump_get_buffer(&iter, true, dst + header_size,
328 					  dst_size, &dump_size))
329 			break;
330 
331 		if (big_oops_buf) {
332 			zipped_len = pstore_compress(dst, psinfo->buf,
333 						header_size + dump_size,
334 						psinfo->bufsize);
335 
336 			if (zipped_len > 0) {
337 				record.compressed = true;
338 				record.size = zipped_len;
339 			} else {
340 				/*
341 				 * Compression failed, so the buffer is most
342 				 * likely filled with binary data that does not
343 				 * compress as well as ASCII text. Copy as much
344 				 * of the uncompressed data as possible into
345 				 * the pstore record, and discard the rest.
346 				 */
347 				record.size = psinfo->bufsize;
348 				memcpy(psinfo->buf, dst, psinfo->bufsize);
349 			}
350 		} else {
351 			record.size = header_size + dump_size;
352 		}
353 
354 		ret = psinfo->write(&record);
355 		if (ret == 0 && reason == KMSG_DUMP_OOPS) {
356 			pstore_new_entry = 1;
357 			pstore_timer_kick();
358 		} else {
359 			/* Preserve only the first non-zero returned value. */
360 			if (!saved_ret)
361 				saved_ret = ret;
362 		}
363 
364 		total += record.size;
365 		part++;
366 	}
367 	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
368 
369 	if (saved_ret) {
370 		pr_err_once("backend (%s) writing error (%d)\n", psinfo->name,
371 			    saved_ret);
372 	}
373 }
374 
375 static struct kmsg_dumper pstore_dumper = {
376 	.dump = pstore_dump,
377 };
378 
379 /*
380  * Register with kmsg_dump to save last part of console log on panic.
381  */
382 static void pstore_register_kmsg(void)
383 {
384 	kmsg_dump_register(&pstore_dumper);
385 }
386 
387 static void pstore_unregister_kmsg(void)
388 {
389 	kmsg_dump_unregister(&pstore_dumper);
390 }
391 
392 #ifdef CONFIG_PSTORE_CONSOLE
393 static void pstore_console_write(struct console *con, const char *s, unsigned c)
394 {
395 	struct pstore_record record;
396 
397 	if (!c)
398 		return;
399 
400 	pstore_record_init(&record, psinfo);
401 	record.type = PSTORE_TYPE_CONSOLE;
402 
403 	record.buf = (char *)s;
404 	record.size = c;
405 	psinfo->write(&record);
406 }
407 
408 static struct console pstore_console = {
409 	.write	= pstore_console_write,
410 	.index	= -1,
411 };
412 
413 static void pstore_register_console(void)
414 {
415 	/* Show which backend is going to get console writes. */
416 	strscpy(pstore_console.name, psinfo->name,
417 		sizeof(pstore_console.name));
418 	/*
419 	 * Always initialize flags here since prior unregister_console()
420 	 * calls may have changed settings (specifically CON_ENABLED).
421 	 */
422 	pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
423 	register_console(&pstore_console);
424 }
425 
426 static void pstore_unregister_console(void)
427 {
428 	unregister_console(&pstore_console);
429 }
430 #else
431 static void pstore_register_console(void) {}
432 static void pstore_unregister_console(void) {}
433 #endif
434 
435 static int pstore_write_user_compat(struct pstore_record *record,
436 				    const char __user *buf)
437 {
438 	int ret = 0;
439 
440 	if (record->buf)
441 		return -EINVAL;
442 
443 	record->buf = vmemdup_user(buf, record->size);
444 	if (IS_ERR(record->buf)) {
445 		ret = PTR_ERR(record->buf);
446 		goto out;
447 	}
448 
449 	ret = record->psi->write(record);
450 
451 	kvfree(record->buf);
452 out:
453 	record->buf = NULL;
454 
455 	return unlikely(ret < 0) ? ret : record->size;
456 }
457 
458 /*
459  * platform specific persistent storage driver registers with
460  * us here. If pstore is already mounted, call the platform
461  * read function right away to populate the file system. If not
462  * then the pstore mount code will call us later to fill out
463  * the file system.
464  */
465 int pstore_register(struct pstore_info *psi)
466 {
467 	char *new_backend;
468 
469 	if (backend && strcmp(backend, psi->name)) {
470 		pr_warn("backend '%s' already in use: ignoring '%s'\n",
471 			backend, psi->name);
472 		return -EBUSY;
473 	}
474 
475 	/* Sanity check flags. */
476 	if (!psi->flags) {
477 		pr_warn("backend '%s' must support at least one frontend\n",
478 			psi->name);
479 		return -EINVAL;
480 	}
481 
482 	/* Check for required functions. */
483 	if (!psi->read || !psi->write) {
484 		pr_warn("backend '%s' must implement read() and write()\n",
485 			psi->name);
486 		return -EINVAL;
487 	}
488 
489 	new_backend = kstrdup(psi->name, GFP_KERNEL);
490 	if (!new_backend)
491 		return -ENOMEM;
492 
493 	mutex_lock(&psinfo_lock);
494 	if (psinfo) {
495 		pr_warn("backend '%s' already loaded: ignoring '%s'\n",
496 			psinfo->name, psi->name);
497 		mutex_unlock(&psinfo_lock);
498 		kfree(new_backend);
499 		return -EBUSY;
500 	}
501 
502 	if (!psi->write_user)
503 		psi->write_user = pstore_write_user_compat;
504 	psinfo = psi;
505 	mutex_init(&psinfo->read_mutex);
506 	spin_lock_init(&psinfo->buf_lock);
507 
508 	if (psi->flags & PSTORE_FLAGS_DMESG)
509 		allocate_buf_for_compression();
510 
511 	pstore_get_records(0);
512 
513 	if (psi->flags & PSTORE_FLAGS_DMESG) {
514 		pstore_dumper.max_reason = psinfo->max_reason;
515 		pstore_register_kmsg();
516 	}
517 	if (psi->flags & PSTORE_FLAGS_CONSOLE)
518 		pstore_register_console();
519 	if (psi->flags & PSTORE_FLAGS_FTRACE)
520 		pstore_register_ftrace();
521 	if (psi->flags & PSTORE_FLAGS_PMSG)
522 		pstore_register_pmsg();
523 
524 	/* Start watching for new records, if desired. */
525 	pstore_timer_kick();
526 
527 	/*
528 	 * Update the module parameter backend, so it is visible
529 	 * through /sys/module/pstore/parameters/backend
530 	 */
531 	backend = new_backend;
532 
533 	pr_info("Registered %s as persistent store backend\n", psi->name);
534 
535 	mutex_unlock(&psinfo_lock);
536 	return 0;
537 }
538 EXPORT_SYMBOL_GPL(pstore_register);
539 
540 void pstore_unregister(struct pstore_info *psi)
541 {
542 	/* It's okay to unregister nothing. */
543 	if (!psi)
544 		return;
545 
546 	mutex_lock(&psinfo_lock);
547 
548 	/* Only one backend can be registered at a time. */
549 	if (WARN_ON(psi != psinfo)) {
550 		mutex_unlock(&psinfo_lock);
551 		return;
552 	}
553 
554 	/* Unregister all callbacks. */
555 	if (psi->flags & PSTORE_FLAGS_PMSG)
556 		pstore_unregister_pmsg();
557 	if (psi->flags & PSTORE_FLAGS_FTRACE)
558 		pstore_unregister_ftrace();
559 	if (psi->flags & PSTORE_FLAGS_CONSOLE)
560 		pstore_unregister_console();
561 	if (psi->flags & PSTORE_FLAGS_DMESG)
562 		pstore_unregister_kmsg();
563 
564 	/* Stop timer and make sure all work has finished. */
565 	del_timer_sync(&pstore_timer);
566 	flush_work(&pstore_work);
567 
568 	/* Remove all backend records from filesystem tree. */
569 	pstore_put_backend_records(psi);
570 
571 	free_buf_for_compression();
572 
573 	psinfo = NULL;
574 	kfree(backend);
575 	backend = NULL;
576 
577 	pr_info("Unregistered %s as persistent store backend\n", psi->name);
578 	mutex_unlock(&psinfo_lock);
579 }
580 EXPORT_SYMBOL_GPL(pstore_unregister);
581 
582 static void decompress_record(struct pstore_record *record,
583 			      struct z_stream_s *zstream)
584 {
585 	int ret;
586 	int unzipped_len;
587 	char *unzipped, *workspace;
588 	size_t max_uncompressed_size;
589 
590 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
591 		return;
592 
593 	/* Only PSTORE_TYPE_DMESG support compression. */
594 	if (record->type != PSTORE_TYPE_DMESG) {
595 		pr_warn("ignored compressed record type %d\n", record->type);
596 		return;
597 	}
598 
599 	/* Missing compression buffer means compression was not initialized. */
600 	if (!zstream->workspace) {
601 		pr_warn("no decompression method initialized!\n");
602 		return;
603 	}
604 
605 	ret = zlib_inflateReset(zstream);
606 	if (ret != Z_OK) {
607 		pr_err("zlib_inflateReset() failed, ret = %d!\n", ret);
608 		return;
609 	}
610 
611 	/* Allocate enough space to hold max decompression and ECC. */
612 	max_uncompressed_size = 3 * psinfo->bufsize;
613 	workspace = kvzalloc(max_uncompressed_size + record->ecc_notice_size,
614 			     GFP_KERNEL);
615 	if (!workspace)
616 		return;
617 
618 	zstream->next_in	= record->buf;
619 	zstream->avail_in	= record->size;
620 	zstream->next_out	= workspace;
621 	zstream->avail_out	= max_uncompressed_size;
622 
623 	ret = zlib_inflate(zstream, Z_FINISH);
624 	if (ret != Z_STREAM_END) {
625 		pr_err_ratelimited("zlib_inflate() failed, ret = %d!\n", ret);
626 		kvfree(workspace);
627 		return;
628 	}
629 
630 	unzipped_len = zstream->total_out;
631 
632 	/* Append ECC notice to decompressed buffer. */
633 	memcpy(workspace + unzipped_len, record->buf + record->size,
634 	       record->ecc_notice_size);
635 
636 	/* Copy decompressed contents into an minimum-sized allocation. */
637 	unzipped = kvmemdup(workspace, unzipped_len + record->ecc_notice_size,
638 			    GFP_KERNEL);
639 	kvfree(workspace);
640 	if (!unzipped)
641 		return;
642 
643 	/* Swap out compressed contents with decompressed contents. */
644 	kvfree(record->buf);
645 	record->buf = unzipped;
646 	record->size = unzipped_len;
647 	record->compressed = false;
648 }
649 
650 /*
651  * Read all the records from one persistent store backend. Create
652  * files in our filesystem.  Don't warn about -EEXIST errors
653  * when we are re-scanning the backing store looking to add new
654  * error records.
655  */
656 void pstore_get_backend_records(struct pstore_info *psi,
657 				struct dentry *root, int quiet)
658 {
659 	int failed = 0;
660 	unsigned int stop_loop = 65536;
661 	struct z_stream_s zstream = {};
662 
663 	if (!psi || !root)
664 		return;
665 
666 	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) {
667 		zstream.workspace = kvmalloc(zlib_inflate_workspacesize(),
668 					     GFP_KERNEL);
669 		zlib_inflateInit2(&zstream, -DEF_WBITS);
670 	}
671 
672 	mutex_lock(&psi->read_mutex);
673 	if (psi->open && psi->open(psi))
674 		goto out;
675 
676 	/*
677 	 * Backend callback read() allocates record.buf. decompress_record()
678 	 * may reallocate record.buf. On success, pstore_mkfile() will keep
679 	 * the record.buf, so free it only on failure.
680 	 */
681 	for (; stop_loop; stop_loop--) {
682 		struct pstore_record *record;
683 		int rc;
684 
685 		record = kzalloc(sizeof(*record), GFP_KERNEL);
686 		if (!record) {
687 			pr_err("out of memory creating record\n");
688 			break;
689 		}
690 		pstore_record_init(record, psi);
691 
692 		record->size = psi->read(record);
693 
694 		/* No more records left in backend? */
695 		if (record->size <= 0) {
696 			kfree(record);
697 			break;
698 		}
699 
700 		decompress_record(record, &zstream);
701 		rc = pstore_mkfile(root, record);
702 		if (rc) {
703 			/* pstore_mkfile() did not take record, so free it. */
704 			kvfree(record->buf);
705 			kfree(record->priv);
706 			kfree(record);
707 			if (rc != -EEXIST || !quiet)
708 				failed++;
709 		}
710 	}
711 	if (psi->close)
712 		psi->close(psi);
713 out:
714 	mutex_unlock(&psi->read_mutex);
715 
716 	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && compress) {
717 		if (zlib_inflateEnd(&zstream) != Z_OK)
718 			pr_warn("zlib_inflateEnd() failed\n");
719 		kvfree(zstream.workspace);
720 	}
721 
722 	if (failed)
723 		pr_warn("failed to create %d record(s) from '%s'\n",
724 			failed, psi->name);
725 	if (!stop_loop)
726 		pr_err("looping? Too many records seen from '%s'\n",
727 			psi->name);
728 }
729 
730 static void pstore_dowork(struct work_struct *work)
731 {
732 	pstore_get_records(1);
733 }
734 
735 static void pstore_timefunc(struct timer_list *unused)
736 {
737 	if (pstore_new_entry) {
738 		pstore_new_entry = 0;
739 		schedule_work(&pstore_work);
740 	}
741 
742 	pstore_timer_kick();
743 }
744 
745 static int __init pstore_init(void)
746 {
747 	int ret;
748 
749 	ret = pstore_init_fs();
750 	if (ret)
751 		free_buf_for_compression();
752 
753 	return ret;
754 }
755 late_initcall(pstore_init);
756 
757 static void __exit pstore_exit(void)
758 {
759 	pstore_exit_fs();
760 }
761 module_exit(pstore_exit)
762 
763 MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
764 MODULE_DESCRIPTION("Persistent Storage - platform driver interface");
765 MODULE_LICENSE("GPL");
766