xref: /openbmc/linux/fs/pstore/platform.c (revision b97d6790d03b763eca08847a9a5869a4291b9f9a)
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  
pstore_set_kmsg_bytes(int bytes)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  
pstore_type_to_name(enum pstore_type_id type)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  
pstore_name_to_type(const char * name)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  
pstore_timer_kick(void)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  
pstore_cannot_block_path(enum kmsg_dump_reason reason)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  
pstore_compress(const void * in,void * out,unsigned int inlen,unsigned int outlen)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  
allocate_buf_for_compression(void)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  
free_buf_for_compression(void)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  
pstore_record_init(struct pstore_record * record,struct pstore_info * psinfo)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   */
pstore_dump(struct kmsg_dumper * dumper,enum kmsg_dump_reason reason)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   */
pstore_register_kmsg(void)382  static void pstore_register_kmsg(void)
383  {
384  	kmsg_dump_register(&pstore_dumper);
385  }
386  
pstore_unregister_kmsg(void)387  static void pstore_unregister_kmsg(void)
388  {
389  	kmsg_dump_unregister(&pstore_dumper);
390  }
391  
392  #ifdef CONFIG_PSTORE_CONSOLE
pstore_console_write(struct console * con,const char * s,unsigned c)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  
pstore_register_console(void)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  
pstore_unregister_console(void)426  static void pstore_unregister_console(void)
427  {
428  	unregister_console(&pstore_console);
429  }
430  #else
pstore_register_console(void)431  static void pstore_register_console(void) {}
pstore_unregister_console(void)432  static void pstore_unregister_console(void) {}
433  #endif
434  
pstore_write_user_compat(struct pstore_record * record,const char __user * buf)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   */
pstore_register(struct pstore_info * psi)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  
pstore_unregister(struct pstore_info * psi)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  
decompress_record(struct pstore_record * record,struct z_stream_s * zstream)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   */
pstore_get_backend_records(struct pstore_info * psi,struct dentry * root,int quiet)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  
pstore_dowork(struct work_struct * work)730  static void pstore_dowork(struct work_struct *work)
731  {
732  	pstore_get_records(1);
733  }
734  
pstore_timefunc(struct timer_list * unused)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  
pstore_init(void)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  
pstore_exit(void)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_LICENSE("GPL");
765