fs/pstore/platform.c

   1 /*
   2  * Persistent Storage - platform driver interface parts.
   3  *
   4  * Copyright (C) 2007-2008 Google, Inc.
   5  * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #define pr_fmt(fmt) "pstore: " fmt
  22
  23 #include <linux/atomic.h>
  24 #include <linux/types.h>
  25 #include <linux/errno.h>
  26 #include <linux/init.h>
  27 #include <linux/kmsg_dump.h>
  28 #include <linux/console.h>
  29 #include <linux/module.h>
  30 #include <linux/pstore.h>
  31 #if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
  32 #include <linux/lzo.h>
  33 #endif
  34 #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
  35 #include <linux/lz4.h>
  36 #endif
  37 #include <linux/crypto.h>
  38 #include <linux/string.h>
  39 #include <linux/timer.h>
  40 #include <linux/slab.h>
  41 #include <linux/uaccess.h>
  42 #include <linux/jiffies.h>
  43 #include <linux/workqueue.h>
  44
  45 #include "internal.h"
  46
  47 /*
  48  * We defer making "oops" entries appear in pstore - see
  49  * whether the system is actually still running well enough
  50  * to let someone see the entry
  51  */
  52 static int pstore_update_ms = -1;
  53 module_param_named(update_ms, pstore_update_ms, int, 0600);
  54 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
  55                  "(default is -1, which means runtime updates are disabled; "
  56                  "enabling this option is not safe, it may lead to further "
  57                  "corruption on Oopses)");
  58
  59 static int pstore_new_entry;
  60
  61 static void pstore_timefunc(struct timer_list *);
  62 static DEFINE_TIMER(pstore_timer, pstore_timefunc);
  63
  64 static void pstore_dowork(struct work_struct *);
  65 static DECLARE_WORK(pstore_work, pstore_dowork);
  66
  67 /*
  68  * pstore_lock just protects "psinfo" during
  69  * calls to pstore_register()
  70  */
  71 static DEFINE_SPINLOCK(pstore_lock);
  72 struct pstore_info *psinfo;
  73
  74 static char *backend;
  75 static char *compress =
  76 #ifdef CONFIG_PSTORE_COMPRESS_DEFAULT
  77                 CONFIG_PSTORE_COMPRESS_DEFAULT;
  78 #else
  79                 NULL;
  80 #endif
  81
  82 /* Compression parameters */
  83 static struct crypto_comp *tfm;
  84
  85 struct pstore_zbackend {
  86         int (*zbufsize)(size_t size);
  87         const char *name;
  88 };
  89
  90 static char *big_oops_buf;
  91 static size_t big_oops_buf_sz;
  92
  93 /* How much of the console log to snapshot */
  94 unsigned long kmsg_bytes = PSTORE_DEFAULT_KMSG_BYTES;
  95
  96 void pstore_set_kmsg_bytes(int bytes)
  97 {
  98         kmsg_bytes = bytes;
  99 }
 100
 101 /* Tag each group of saved records with a sequence number */
 102 static int      oopscount;
 103
 104 static const char *get_reason_str(enum kmsg_dump_reason reason)
 105 {
 106         switch (reason) {
 107         case KMSG_DUMP_PANIC:
 108                 return "Panic";
 109         case KMSG_DUMP_OOPS:
 110                 return "Oops";
 111         case KMSG_DUMP_EMERG:
 112                 return "Emergency";
 113         case KMSG_DUMP_RESTART:
 114                 return "Restart";
 115         case KMSG_DUMP_HALT:
 116                 return "Halt";
 117         case KMSG_DUMP_POWEROFF:
 118                 return "Poweroff";
 119         default:
 120                 return "Unknown";
 121         }
 122 }
 123
 124 bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
 125 {
 126         /*
 127          * In case of NMI path, pstore shouldn't be blocked
 128          * regardless of reason.
 129          */
 130         if (in_nmi())
 131                 return true;
 132
 133         switch (reason) {
 134         /* In panic case, other cpus are stopped by smp_send_stop(). */
 135         case KMSG_DUMP_PANIC:
 136         /* Emergency restart shouldn't be blocked by spin lock. */
 137         case KMSG_DUMP_EMERG:
 138                 return true;
 139         default:
 140                 return false;
 141         }
 142 }
 143 EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
 144
 145 #if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
 146 static int zbufsize_deflate(size_t size)
 147 {
 148         size_t cmpr;
 149
 150         switch (size) {
 151         /* buffer range for efivars */
 152         case 1000 ... 2000:
 153                 cmpr = 56;
 154                 break;
 155         case 2001 ... 3000:
 156                 cmpr = 54;
 157                 break;
 158         case 3001 ... 3999:
 159                 cmpr = 52;
 160                 break;
 161         /* buffer range for nvram, erst */
 162         case 4000 ... 10000:
 163                 cmpr = 45;
 164                 break;
 165         default:
 166                 cmpr = 60;
 167                 break;
 168         }
 169
 170         return (size * 100) / cmpr;
 171 }
 172 #endif
 173
 174 #if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
 175 static int zbufsize_lzo(size_t size)
 176 {
 177         return lzo1x_worst_compress(size);
 178 }
 179 #endif
 180
 181 #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS) || IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
 182 static int zbufsize_lz4(size_t size)
 183 {
 184         return LZ4_compressBound(size);
 185 }
 186 #endif
 187
 188 #if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
 189 static int zbufsize_842(size_t size)
 190 {
 191         return size;
 192 }
 193 #endif
 194
 195 static const struct pstore_zbackend *zbackend __ro_after_init;
 196
 197 static const struct pstore_zbackend zbackends[] = {
 198 #if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS)
 199         {
 200                 .zbufsize       = zbufsize_deflate,
 201                 .name           = "deflate",
 202         },
 203 #endif
 204 #if IS_ENABLED(CONFIG_PSTORE_LZO_COMPRESS)
 205         {
 206                 .zbufsize       = zbufsize_lzo,
 207                 .name           = "lzo",
 208         },
 209 #endif
 210 #if IS_ENABLED(CONFIG_PSTORE_LZ4_COMPRESS)
 211         {
 212                 .zbufsize       = zbufsize_lz4,
 213                 .name           = "lz4",
 214         },
 215 #endif
 216 #if IS_ENABLED(CONFIG_PSTORE_LZ4HC_COMPRESS)
 217         {
 218                 .zbufsize       = zbufsize_lz4,
 219                 .name           = "lz4hc",
 220         },
 221 #endif
 222 #if IS_ENABLED(CONFIG_PSTORE_842_COMPRESS)
 223         {
 224                 .zbufsize       = zbufsize_842,
 225                 .name           = "842",
 226         },
 227 #endif
 228         { }
 229 };
 230
 231 static int pstore_compress(const void *in, void *out,
 232                            unsigned int inlen, unsigned int outlen)
 233 {
 234         int ret;
 235
 236         ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
 237         if (ret) {
 238                 pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
 239                 return ret;
 240         }
 241
 242         return outlen;
 243 }
 244
 245 static int pstore_decompress(void *in, void *out,
 246                              unsigned int inlen, unsigned int outlen)
 247 {
 248         int ret;
 249
 250         ret = crypto_comp_decompress(tfm, in, inlen, out, &outlen);
 251         if (ret) {
 252                 pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
 253                 return ret;
 254         }
 255
 256         return outlen;
 257 }
 258
 259 static void allocate_buf_for_compression(void)
 260 {
 261         if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
 262                 return;
 263
 264         if (!crypto_has_comp(zbackend->name, 0, 0)) {
 265                 pr_err("No %s compression\n", zbackend->name);
 266                 return;
 267         }
 268
 269         big_oops_buf_sz = zbackend->zbufsize(psinfo->bufsize);
 270         if (big_oops_buf_sz <= 0)
 271                 return;
 272
 273         big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
 274         if (!big_oops_buf) {
 275                 pr_err("allocate compression buffer error!\n");
 276                 return;
 277         }
 278
 279         tfm = crypto_alloc_comp(zbackend->name, 0, 0);
 280         if (IS_ERR_OR_NULL(tfm)) {
 281                 kfree(big_oops_buf);
 282                 big_oops_buf = NULL;
 283                 pr_err("crypto_alloc_comp() failed!\n");
 284                 return;
 285         }
 286 }
 287
 288 static void free_buf_for_compression(void)
 289 {
 290         if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && !IS_ERR_OR_NULL(tfm))
 291                 crypto_free_comp(tfm);
 292         kfree(big_oops_buf);
 293         big_oops_buf = NULL;
 294         big_oops_buf_sz = 0;
 295 }
 296
 297 /*
 298  * Called when compression fails, since the printk buffer
 299  * would be fetched for compression calling it again when
 300  * compression fails would have moved the iterator of
 301  * printk buffer which results in fetching old contents.
 302  * Copy the recent messages from big_oops_buf to psinfo->buf
 303  */
 304 static size_t copy_kmsg_to_buffer(int hsize, size_t len)
 305 {
 306         size_t total_len;
 307         size_t diff;
 308
 309         total_len = hsize + len;
 310
 311         if (total_len > psinfo->bufsize) {
 312                 diff = total_len - psinfo->bufsize + hsize;
 313                 memcpy(psinfo->buf, big_oops_buf, hsize);
 314                 memcpy(psinfo->buf + hsize, big_oops_buf + diff,
 315                                         psinfo->bufsize - hsize);
 316                 total_len = psinfo->bufsize;
 317         } else
 318                 memcpy(psinfo->buf, big_oops_buf, total_len);
 319
 320         return total_len;
 321 }
 322
 323 void pstore_record_init(struct pstore_record *record,
 324                         struct pstore_info *psinfo)
 325 {
 326         memset(record, 0, sizeof(*record));
 327
 328         record->psi = psinfo;
 329
 330         /* Report zeroed timestamp if called before timekeeping has resumed. */
 331         record->time = ns_to_timespec64(ktime_get_real_fast_ns());
 332 }
 333
 334 /*
 335  * callback from kmsg_dump. (s2,l2) has the most recently
 336  * written bytes, older bytes are in (s1,l1). Save as much
 337  * as we can from the end of the buffer.
 338  */
 339 static void pstore_dump(struct kmsg_dumper *dumper,
 340                         enum kmsg_dump_reason reason)
 341 {
 342         unsigned long   total = 0;
 343         const char      *why;
 344         unsigned int    part = 1;
 345         unsigned long   flags = 0;
 346         int             is_locked;
 347         int             ret;
 348
 349         why = get_reason_str(reason);
 350
 351         if (pstore_cannot_block_path(reason)) {
 352                 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
 353                 if (!is_locked) {
 354                         pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
 355                                        , in_nmi() ? "NMI" : why);
 356                         return;
 357                 }
 358         } else {
 359                 spin_lock_irqsave(&psinfo->buf_lock, flags);
 360                 is_locked = 1;
 361         }
 362         oopscount++;
 363         while (total < kmsg_bytes) {
 364                 char *dst;
 365                 size_t dst_size;
 366                 int header_size;
 367                 int zipped_len = -1;
 368                 size_t dump_size;
 369                 struct pstore_record record;
 370
 371                 pstore_record_init(&record, psinfo);
 372                 record.type = PSTORE_TYPE_DMESG;
 373                 record.count = oopscount;
 374                 record.reason = reason;
 375                 record.part = part;
 376                 record.buf = psinfo->buf;
 377
 378                 if (big_oops_buf && is_locked) {
 379                         dst = big_oops_buf;
 380                         dst_size = big_oops_buf_sz;
 381                 } else {
 382                         dst = psinfo->buf;
 383                         dst_size = psinfo->bufsize;
 384                 }
 385
 386                 /* Write dump header. */
 387                 header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
 388                                  oopscount, part);
 389                 dst_size -= header_size;
 390
 391                 /* Write dump contents. */
 392                 if (!kmsg_dump_get_buffer(dumper, true, dst + header_size,
 393                                           dst_size, &dump_size))
 394                         break;
 395
 396                 if (big_oops_buf && is_locked) {
 397                         zipped_len = pstore_compress(dst, psinfo->buf,
 398                                                 header_size + dump_size,
 399                                                 psinfo->bufsize);
 400
 401                         if (zipped_len > 0) {
 402                                 record.compressed = true;
 403                                 record.size = zipped_len;
 404                         } else {
 405                                 record.size = copy_kmsg_to_buffer(header_size,
 406                                                                   dump_size);
 407                         }
 408                 } else {
 409                         record.size = header_size + dump_size;
 410                 }
 411
 412                 ret = psinfo->write(&record);
 413                 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
 414                         pstore_new_entry = 1;
 415
 416                 total += record.size;
 417                 part++;
 418         }
 419         if (is_locked)
 420                 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 421 }
 422
 423 static struct kmsg_dumper pstore_dumper = {
 424         .dump = pstore_dump,
 425 };
 426
 427 /*
 428  * Register with kmsg_dump to save last part of console log on panic.
 429  */
 430 static void pstore_register_kmsg(void)
 431 {
 432         kmsg_dump_register(&pstore_dumper);
 433 }
 434
 435 static void pstore_unregister_kmsg(void)
 436 {
 437         kmsg_dump_unregister(&pstore_dumper);
 438 }
 439
 440 #ifdef CONFIG_PSTORE_CONSOLE
 441 static void pstore_console_write(struct console *con, const char *s, unsigned c)
 442 {
 443         const char *e = s + c;
 444
 445         while (s < e) {
 446                 struct pstore_record record;
 447                 unsigned long flags;
 448
 449                 pstore_record_init(&record, psinfo);
 450                 record.type = PSTORE_TYPE_CONSOLE;
 451
 452                 if (c > psinfo->bufsize)
 453                         c = psinfo->bufsize;
 454
 455                 if (oops_in_progress) {
 456                         if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
 457                                 break;
 458                 } else {
 459                         spin_lock_irqsave(&psinfo->buf_lock, flags);
 460                 }
 461                 record.buf = (char *)s;
 462                 record.size = c;
 463                 psinfo->write(&record);
 464                 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 465                 s += c;
 466                 c = e - s;
 467         }
 468 }
 469
 470 static struct console pstore_console = {
 471         .name   = "pstore",
 472         .write  = pstore_console_write,
 473         .flags  = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
 474         .index  = -1,
 475 };
 476
 477 static void pstore_register_console(void)
 478 {
 479         register_console(&pstore_console);
 480 }
 481
 482 static void pstore_unregister_console(void)
 483 {
 484         unregister_console(&pstore_console);
 485 }
 486 #else
 487 static void pstore_register_console(void) {}
 488 static void pstore_unregister_console(void) {}
 489 #endif
 490
 491 static int pstore_write_user_compat(struct pstore_record *record,
 492                                     const char __user *buf)
 493 {
 494         int ret = 0;
 495
 496         if (record->buf)
 497                 return -EINVAL;
 498
 499         record->buf = memdup_user(buf, record->size);
 500         if (IS_ERR(record->buf)) {
 501                 ret = PTR_ERR(record->buf);
 502                 goto out;
 503         }
 504
 505         ret = record->psi->write(record);
 506
 507         kfree(record->buf);
 508 out:
 509         record->buf = NULL;
 510
 511         return unlikely(ret < 0) ? ret : record->size;
 512 }
 513
 514 /*
 515  * platform specific persistent storage driver registers with
 516  * us here. If pstore is already mounted, call the platform
 517  * read function right away to populate the file system. If not
 518  * then the pstore mount code will call us later to fill out
 519  * the file system.
 520  */
 521 int pstore_register(struct pstore_info *psi)
 522 {
 523         struct module *owner = psi->owner;
 524
 525         if (backend && strcmp(backend, psi->name)) {
 526                 pr_warn("ignoring unexpected backend '%s'\n", psi->name);
 527                 return -EPERM;
 528         }
 529
 530         /* Sanity check flags. */
 531         if (!psi->flags) {
 532                 pr_warn("backend '%s' must support at least one frontend\n",
 533                         psi->name);
 534                 return -EINVAL;
 535         }
 536
 537         /* Check for required functions. */
 538         if (!psi->read || !psi->write) {
 539                 pr_warn("backend '%s' must implement read() and write()\n",
 540                         psi->name);
 541                 return -EINVAL;
 542         }
 543
 544         spin_lock(&pstore_lock);
 545         if (psinfo) {
 546                 pr_warn("backend '%s' already loaded: ignoring '%s'\n",
 547                         psinfo->name, psi->name);
 548                 spin_unlock(&pstore_lock);
 549                 return -EBUSY;
 550         }
 551
 552         if (!psi->write_user)
 553                 psi->write_user = pstore_write_user_compat;
 554         psinfo = psi;
 555         mutex_init(&psinfo->read_mutex);
 556         spin_unlock(&pstore_lock);
 557
 558         if (owner && !try_module_get(owner)) {
 559                 psinfo = NULL;
 560                 return -EINVAL;
 561         }
 562
 563         allocate_buf_for_compression();
 564
 565         if (pstore_is_mounted())
 566                 pstore_get_records(0);
 567
 568         if (psi->flags & PSTORE_FLAGS_DMESG)
 569                 pstore_register_kmsg();
 570         if (psi->flags & PSTORE_FLAGS_CONSOLE)
 571                 pstore_register_console();
 572         if (psi->flags & PSTORE_FLAGS_FTRACE)
 573                 pstore_register_ftrace();
 574         if (psi->flags & PSTORE_FLAGS_PMSG)
 575                 pstore_register_pmsg();
 576
 577         /* Start watching for new records, if desired. */
 578         if (pstore_update_ms >= 0) {
 579                 pstore_timer.expires = jiffies +
 580                         msecs_to_jiffies(pstore_update_ms);
 581                 add_timer(&pstore_timer);
 582         }
 583
 584         /*
 585          * Update the module parameter backend, so it is visible
 586          * through /sys/module/pstore/parameters/backend
 587          */
 588         backend = psi->name;
 589
 590         pr_info("Registered %s as persistent store backend\n", psi->name);
 591
 592         module_put(owner);
 593
 594         return 0;
 595 }
 596 EXPORT_SYMBOL_GPL(pstore_register);
 597
 598 void pstore_unregister(struct pstore_info *psi)
 599 {
 600         /* Stop timer and make sure all work has finished. */
 601         pstore_update_ms = -1;
 602         del_timer_sync(&pstore_timer);
 603         flush_work(&pstore_work);
 604
 605         if (psi->flags & PSTORE_FLAGS_PMSG)
 606                 pstore_unregister_pmsg();
 607         if (psi->flags & PSTORE_FLAGS_FTRACE)
 608                 pstore_unregister_ftrace();
 609         if (psi->flags & PSTORE_FLAGS_CONSOLE)
 610                 pstore_unregister_console();
 611         if (psi->flags & PSTORE_FLAGS_DMESG)
 612                 pstore_unregister_kmsg();
 613
 614         free_buf_for_compression();
 615
 616         psinfo = NULL;
 617         backend = NULL;
 618 }
 619 EXPORT_SYMBOL_GPL(pstore_unregister);
 620
 621 static void decompress_record(struct pstore_record *record)
 622 {
 623         int unzipped_len;
 624         char *decompressed;
 625
 626         if (!record->compressed)
 627                 return;
 628
 629         /* Only PSTORE_TYPE_DMESG support compression. */
 630         if (record->type != PSTORE_TYPE_DMESG) {
 631                 pr_warn("ignored compressed record type %d\n", record->type);
 632                 return;
 633         }
 634
 635         /* No compression method has created the common buffer. */
 636         if (!big_oops_buf) {
 637                 pr_warn("no decompression buffer allocated\n");
 638                 return;
 639         }
 640
 641         unzipped_len = pstore_decompress(record->buf, big_oops_buf,
 642                                          record->size, big_oops_buf_sz);
 643         if (unzipped_len <= 0) {
 644                 pr_err("decompression failed: %d\n", unzipped_len);
 645                 return;
 646         }
 647
 648         /* Build new buffer for decompressed contents. */
 649         decompressed = kmalloc(unzipped_len + record->ecc_notice_size,
 650                                GFP_KERNEL);
 651         if (!decompressed) {
 652                 pr_err("decompression ran out of memory\n");
 653                 return;
 654         }
 655         memcpy(decompressed, big_oops_buf, unzipped_len);
 656
 657         /* Append ECC notice to decompressed buffer. */
 658         memcpy(decompressed + unzipped_len, record->buf + record->size,
 659                record->ecc_notice_size);
 660
 661         /* Swap out compresed contents with decompressed contents. */
 662         kfree(record->buf);
 663         record->buf = decompressed;
 664         record->size = unzipped_len;
 665         record->compressed = false;
 666 }
 667
 668 /*
 669  * Read all the records from one persistent store backend. Create
 670  * files in our filesystem.  Don't warn about -EEXIST errors
 671  * when we are re-scanning the backing store looking to add new
 672  * error records.
 673  */
 674 void pstore_get_backend_records(struct pstore_info *psi,
 675                                 struct dentry *root, int quiet)
 676 {
 677         int failed = 0;
 678         unsigned int stop_loop = 65536;
 679
 680         if (!psi || !root)
 681                 return;
 682
 683         mutex_lock(&psi->read_mutex);
 684         if (psi->open && psi->open(psi))
 685                 goto out;
 686
 687         /*
 688          * Backend callback read() allocates record.buf. decompress_record()
 689          * may reallocate record.buf. On success, pstore_mkfile() will keep
 690          * the record.buf, so free it only on failure.
 691          */
 692         for (; stop_loop; stop_loop--) {
 693                 struct pstore_record *record;
 694                 int rc;
 695
 696                 record = kzalloc(sizeof(*record), GFP_KERNEL);
 697                 if (!record) {
 698                         pr_err("out of memory creating record\n");
 699                         break;
 700                 }
 701                 pstore_record_init(record, psi);
 702
 703                 record->size = psi->read(record);
 704
 705                 /* No more records left in backend? */
 706                 if (record->size <= 0) {
 707                         kfree(record);
 708                         break;
 709                 }
 710
 711                 decompress_record(record);
 712                 rc = pstore_mkfile(root, record);
 713                 if (rc) {
 714                         /* pstore_mkfile() did not take record, so free it. */
 715                         kfree(record->buf);
 716                         kfree(record);
 717                         if (rc != -EEXIST || !quiet)
 718                                 failed++;
 719                 }
 720         }
 721         if (psi->close)
 722                 psi->close(psi);
 723 out:
 724         mutex_unlock(&psi->read_mutex);
 725
 726         if (failed)
 727                 pr_warn("failed to create %d record(s) from '%s'\n",
 728                         failed, psi->name);
 729         if (!stop_loop)
 730                 pr_err("looping? Too many records seen from '%s'\n",
 731                         psi->name);
 732 }
 733
 734 static void pstore_dowork(struct work_struct *work)
 735 {
 736         pstore_get_records(1);
 737 }
 738
 739 static void pstore_timefunc(struct timer_list *unused)
 740 {
 741         if (pstore_new_entry) {
 742                 pstore_new_entry = 0;
 743                 schedule_work(&pstore_work);
 744         }
 745
 746         if (pstore_update_ms >= 0)
 747                 mod_timer(&pstore_timer,
 748                           jiffies + msecs_to_jiffies(pstore_update_ms));
 749 }
 750
 751 void __init pstore_choose_compression(void)
 752 {
 753         const struct pstore_zbackend *step;
 754
 755         if (!compress)
 756                 return;
 757
 758         for (step = zbackends; step->name; step++) {
 759                 if (!strcmp(compress, step->name)) {
 760                         zbackend = step;
 761                         pr_info("using %s compression\n", zbackend->name);
 762                         return;
 763                 }
 764         }
 765 }
 766
 767 module_param(compress, charp, 0444);
 768 MODULE_PARM_DESC(compress, "Pstore compression to use");
 769
 770 module_param(backend, charp, 0444);
 771 MODULE_PARM_DESC(backend, "Pstore backend to use");