drivers/base/devres.c

   1 /*
   2  * drivers/base/devres.c - device resource management
   3  *
   4  * Copyright (c) 2006  SUSE Linux Products GmbH
   5  * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
   6  *
   7  * This file is released under the GPLv2.
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13
  14 #include "base.h"
  15
  16 struct devres_node {
  17         struct list_head                entry;
  18         dr_release_t                    release;
  19 #ifdef CONFIG_DEBUG_DEVRES
  20         const char                      *name;
  21         size_t                          size;
  22 #endif
  23 };
  24
  25 struct devres {
  26         struct devres_node              node;
  27         /* -- 3 pointers */
  28         unsigned long long              data[]; /* guarantee ull alignment */
  29 };
  30
  31 struct devres_group {
  32         struct devres_node              node[2];
  33         void                            *id;
  34         int                             color;
  35         /* -- 8 pointers */
  36 };
  37
  38 #ifdef CONFIG_DEBUG_DEVRES
  39 static int log_devres = 0;
  40 module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR);
  41
  42 static void set_node_dbginfo(struct devres_node *node, const char *name,
  43                              size_t size)
  44 {
  45         node->name = name;
  46         node->size = size;
  47 }
  48
  49 static void devres_log(struct device *dev, struct devres_node *node,
  50                        const char *op)
  51 {
  52         if (unlikely(log_devres))
  53                 dev_err(dev, "DEVRES %3s %p %s (%lu bytes)\n",
  54                         op, node, node->name, (unsigned long)node->size);
  55 }
  56 #else /* CONFIG_DEBUG_DEVRES */
  57 #define set_node_dbginfo(node, n, s)    do {} while (0)
  58 #define devres_log(dev, node, op)       do {} while (0)
  59 #endif /* CONFIG_DEBUG_DEVRES */
  60
  61 /*
  62  * Release functions for devres group.  These callbacks are used only
  63  * for identification.
  64  */
  65 static void group_open_release(struct device *dev, void *res)
  66 {
  67         /* noop */
  68 }
  69
  70 static void group_close_release(struct device *dev, void *res)
  71 {
  72         /* noop */
  73 }
  74
  75 static struct devres_group * node_to_group(struct devres_node *node)
  76 {
  77         if (node->release == &group_open_release)
  78                 return container_of(node, struct devres_group, node[0]);
  79         if (node->release == &group_close_release)
  80                 return container_of(node, struct devres_group, node[1]);
  81         return NULL;
  82 }
  83
  84 static __always_inline struct devres * alloc_dr(dr_release_t release,
  85                                                 size_t size, gfp_t gfp)
  86 {
  87         size_t tot_size = sizeof(struct devres) + size;
  88         struct devres *dr;
  89
  90         dr = kmalloc_track_caller(tot_size, gfp);
  91         if (unlikely(!dr))
  92                 return NULL;
  93
  94         memset(dr, 0, tot_size);
  95         INIT_LIST_HEAD(&dr->node.entry);
  96         dr->node.release = release;
  97         return dr;
  98 }
  99
 100 static void add_dr(struct device *dev, struct devres_node *node)
 101 {
 102         devres_log(dev, node, "ADD");
 103         BUG_ON(!list_empty(&node->entry));
 104         list_add_tail(&node->entry, &dev->devres_head);
 105 }
 106
 107 #ifdef CONFIG_DEBUG_DEVRES
 108 void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
 109                       const char *name)
 110 {
 111         struct devres *dr;
 112
 113         dr = alloc_dr(release, size, gfp);
 114         if (unlikely(!dr))
 115                 return NULL;
 116         set_node_dbginfo(&dr->node, name, size);
 117         return dr->data;
 118 }
 119 EXPORT_SYMBOL_GPL(__devres_alloc);
 120 #else
 121 /**
 122  * devres_alloc - Allocate device resource data
 123  * @release: Release function devres will be associated with
 124  * @size: Allocation size
 125  * @gfp: Allocation flags
 126  *
 127  * Allocate devres of @size bytes.  The allocated area is zeroed, then
 128  * associated with @release.  The returned pointer can be passed to
 129  * other devres_*() functions.
 130  *
 131  * RETURNS:
 132  * Pointer to allocated devres on success, NULL on failure.
 133  */
 134 void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
 135 {
 136         struct devres *dr;
 137
 138         dr = alloc_dr(release, size, gfp);
 139         if (unlikely(!dr))
 140                 return NULL;
 141         return dr->data;
 142 }
 143 EXPORT_SYMBOL_GPL(devres_alloc);
 144 #endif
 145
 146 /**
 147  * devres_for_each_res - Resource iterator
 148  * @dev: Device to iterate resource from
 149  * @release: Look for resources associated with this release function
 150  * @match: Match function (optional)
 151  * @match_data: Data for the match function
 152  * @fn: Function to be called for each matched resource.
 153  * @data: Data for @fn, the 3rd parameter of @fn
 154  *
 155  * Call @fn for each devres of @dev which is associated with @release
 156  * and for which @match returns 1.
 157  *
 158  * RETURNS:
 159  *      void
 160  */
 161 void devres_for_each_res(struct device *dev, dr_release_t release,
 162                         dr_match_t match, void *match_data,
 163                         void (*fn)(struct device *, void *, void *),
 164                         void *data)
 165 {
 166         struct devres_node *node;
 167         struct devres_node *tmp;
 168         unsigned long flags;
 169
 170         if (!fn)
 171                 return;
 172
 173         spin_lock_irqsave(&dev->devres_lock, flags);
 174         list_for_each_entry_safe_reverse(node, tmp,
 175                         &dev->devres_head, entry) {
 176                 struct devres *dr = container_of(node, struct devres, node);
 177
 178                 if (node->release != release)
 179                         continue;
 180                 if (match && !match(dev, dr->data, match_data))
 181                         continue;
 182                 fn(dev, dr->data, data);
 183         }
 184         spin_unlock_irqrestore(&dev->devres_lock, flags);
 185 }
 186 EXPORT_SYMBOL_GPL(devres_for_each_res);
 187
 188 /**
 189  * devres_free - Free device resource data
 190  * @res: Pointer to devres data to free
 191  *
 192  * Free devres created with devres_alloc().
 193  */
 194 void devres_free(void *res)
 195 {
 196         if (res) {
 197                 struct devres *dr = container_of(res, struct devres, data);
 198
 199                 BUG_ON(!list_empty(&dr->node.entry));
 200                 kfree(dr);
 201         }
 202 }
 203 EXPORT_SYMBOL_GPL(devres_free);
 204
 205 /**
 206  * devres_add - Register device resource
 207  * @dev: Device to add resource to
 208  * @res: Resource to register
 209  *
 210  * Register devres @res to @dev.  @res should have been allocated
 211  * using devres_alloc().  On driver detach, the associated release
 212  * function will be invoked and devres will be freed automatically.
 213  */
 214 void devres_add(struct device *dev, void *res)
 215 {
 216         struct devres *dr = container_of(res, struct devres, data);
 217         unsigned long flags;
 218
 219         spin_lock_irqsave(&dev->devres_lock, flags);
 220         add_dr(dev, &dr->node);
 221         spin_unlock_irqrestore(&dev->devres_lock, flags);
 222 }
 223 EXPORT_SYMBOL_GPL(devres_add);
 224
 225 static struct devres *find_dr(struct device *dev, dr_release_t release,
 226                               dr_match_t match, void *match_data)
 227 {
 228         struct devres_node *node;
 229
 230         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 231                 struct devres *dr = container_of(node, struct devres, node);
 232
 233                 if (node->release != release)
 234                         continue;
 235                 if (match && !match(dev, dr->data, match_data))
 236                         continue;
 237                 return dr;
 238         }
 239
 240         return NULL;
 241 }
 242
 243 /**
 244  * devres_find - Find device resource
 245  * @dev: Device to lookup resource from
 246  * @release: Look for resources associated with this release function
 247  * @match: Match function (optional)
 248  * @match_data: Data for the match function
 249  *
 250  * Find the latest devres of @dev which is associated with @release
 251  * and for which @match returns 1.  If @match is NULL, it's considered
 252  * to match all.
 253  *
 254  * RETURNS:
 255  * Pointer to found devres, NULL if not found.
 256  */
 257 void * devres_find(struct device *dev, dr_release_t release,
 258                    dr_match_t match, void *match_data)
 259 {
 260         struct devres *dr;
 261         unsigned long flags;
 262
 263         spin_lock_irqsave(&dev->devres_lock, flags);
 264         dr = find_dr(dev, release, match, match_data);
 265         spin_unlock_irqrestore(&dev->devres_lock, flags);
 266
 267         if (dr)
 268                 return dr->data;
 269         return NULL;
 270 }
 271 EXPORT_SYMBOL_GPL(devres_find);
 272
 273 /**
 274  * devres_get - Find devres, if non-existent, add one atomically
 275  * @dev: Device to lookup or add devres for
 276  * @new_res: Pointer to new initialized devres to add if not found
 277  * @match: Match function (optional)
 278  * @match_data: Data for the match function
 279  *
 280  * Find the latest devres of @dev which has the same release function
 281  * as @new_res and for which @match return 1.  If found, @new_res is
 282  * freed; otherwise, @new_res is added atomically.
 283  *
 284  * RETURNS:
 285  * Pointer to found or added devres.
 286  */
 287 void * devres_get(struct device *dev, void *new_res,
 288                   dr_match_t match, void *match_data)
 289 {
 290         struct devres *new_dr = container_of(new_res, struct devres, data);
 291         struct devres *dr;
 292         unsigned long flags;
 293
 294         spin_lock_irqsave(&dev->devres_lock, flags);
 295         dr = find_dr(dev, new_dr->node.release, match, match_data);
 296         if (!dr) {
 297                 add_dr(dev, &new_dr->node);
 298                 dr = new_dr;
 299                 new_dr = NULL;
 300         }
 301         spin_unlock_irqrestore(&dev->devres_lock, flags);
 302         devres_free(new_dr);
 303
 304         return dr->data;
 305 }
 306 EXPORT_SYMBOL_GPL(devres_get);
 307
 308 /**
 309  * devres_remove - Find a device resource and remove it
 310  * @dev: Device to find resource from
 311  * @release: Look for resources associated with this release function
 312  * @match: Match function (optional)
 313  * @match_data: Data for the match function
 314  *
 315  * Find the latest devres of @dev associated with @release and for
 316  * which @match returns 1.  If @match is NULL, it's considered to
 317  * match all.  If found, the resource is removed atomically and
 318  * returned.
 319  *
 320  * RETURNS:
 321  * Pointer to removed devres on success, NULL if not found.
 322  */
 323 void * devres_remove(struct device *dev, dr_release_t release,
 324                      dr_match_t match, void *match_data)
 325 {
 326         struct devres *dr;
 327         unsigned long flags;
 328
 329         spin_lock_irqsave(&dev->devres_lock, flags);
 330         dr = find_dr(dev, release, match, match_data);
 331         if (dr) {
 332                 list_del_init(&dr->node.entry);
 333                 devres_log(dev, &dr->node, "REM");
 334         }
 335         spin_unlock_irqrestore(&dev->devres_lock, flags);
 336
 337         if (dr)
 338                 return dr->data;
 339         return NULL;
 340 }
 341 EXPORT_SYMBOL_GPL(devres_remove);
 342
 343 /**
 344  * devres_destroy - Find a device resource and destroy it
 345  * @dev: Device to find resource from
 346  * @release: Look for resources associated with this release function
 347  * @match: Match function (optional)
 348  * @match_data: Data for the match function
 349  *
 350  * Find the latest devres of @dev associated with @release and for
 351  * which @match returns 1.  If @match is NULL, it's considered to
 352  * match all.  If found, the resource is removed atomically and freed.
 353  *
 354  * Note that the release function for the resource will not be called,
 355  * only the devres-allocated data will be freed.  The caller becomes
 356  * responsible for freeing any other data.
 357  *
 358  * RETURNS:
 359  * 0 if devres is found and freed, -ENOENT if not found.
 360  */
 361 int devres_destroy(struct device *dev, dr_release_t release,
 362                    dr_match_t match, void *match_data)
 363 {
 364         void *res;
 365
 366         res = devres_remove(dev, release, match, match_data);
 367         if (unlikely(!res))
 368                 return -ENOENT;
 369
 370         devres_free(res);
 371         return 0;
 372 }
 373 EXPORT_SYMBOL_GPL(devres_destroy);
 374
 375
 376 /**
 377  * devres_release - Find a device resource and destroy it, calling release
 378  * @dev: Device to find resource from
 379  * @release: Look for resources associated with this release function
 380  * @match: Match function (optional)
 381  * @match_data: Data for the match function
 382  *
 383  * Find the latest devres of @dev associated with @release and for
 384  * which @match returns 1.  If @match is NULL, it's considered to
 385  * match all.  If found, the resource is removed atomically, the
 386  * release function called and the resource freed.
 387  *
 388  * RETURNS:
 389  * 0 if devres is found and freed, -ENOENT if not found.
 390  */
 391 int devres_release(struct device *dev, dr_release_t release,
 392                    dr_match_t match, void *match_data)
 393 {
 394         void *res;
 395
 396         res = devres_remove(dev, release, match, match_data);
 397         if (unlikely(!res))
 398                 return -ENOENT;
 399
 400         (*release)(dev, res);
 401         devres_free(res);
 402         return 0;
 403 }
 404 EXPORT_SYMBOL_GPL(devres_release);
 405
 406 static int remove_nodes(struct device *dev,
 407                         struct list_head *first, struct list_head *end,
 408                         struct list_head *todo)
 409 {
 410         int cnt = 0, nr_groups = 0;
 411         struct list_head *cur;
 412
 413         /* First pass - move normal devres entries to @todo and clear
 414          * devres_group colors.
 415          */
 416         cur = first;
 417         while (cur != end) {
 418                 struct devres_node *node;
 419                 struct devres_group *grp;
 420
 421                 node = list_entry(cur, struct devres_node, entry);
 422                 cur = cur->next;
 423
 424                 grp = node_to_group(node);
 425                 if (grp) {
 426                         /* clear color of group markers in the first pass */
 427                         grp->color = 0;
 428                         nr_groups++;
 429                 } else {
 430                         /* regular devres entry */
 431                         if (&node->entry == first)
 432                                 first = first->next;
 433                         list_move_tail(&node->entry, todo);
 434                         cnt++;
 435                 }
 436         }
 437
 438         if (!nr_groups)
 439                 return cnt;
 440
 441         /* Second pass - Scan groups and color them.  A group gets
 442          * color value of two iff the group is wholly contained in
 443          * [cur, end).  That is, for a closed group, both opening and
 444          * closing markers should be in the range, while just the
 445          * opening marker is enough for an open group.
 446          */
 447         cur = first;
 448         while (cur != end) {
 449                 struct devres_node *node;
 450                 struct devres_group *grp;
 451
 452                 node = list_entry(cur, struct devres_node, entry);
 453                 cur = cur->next;
 454
 455                 grp = node_to_group(node);
 456                 BUG_ON(!grp || list_empty(&grp->node[0].entry));
 457
 458                 grp->color++;
 459                 if (list_empty(&grp->node[1].entry))
 460                         grp->color++;
 461
 462                 BUG_ON(grp->color <= 0 || grp->color > 2);
 463                 if (grp->color == 2) {
 464                         /* No need to update cur or end.  The removed
 465                          * nodes are always before both.
 466                          */
 467                         list_move_tail(&grp->node[0].entry, todo);
 468                         list_del_init(&grp->node[1].entry);
 469                 }
 470         }
 471
 472         return cnt;
 473 }
 474
 475 static int release_nodes(struct device *dev, struct list_head *first,
 476                          struct list_head *end, unsigned long flags)
 477         __releases(&dev->devres_lock)
 478 {
 479         LIST_HEAD(todo);
 480         int cnt;
 481         struct devres *dr, *tmp;
 482
 483         cnt = remove_nodes(dev, first, end, &todo);
 484
 485         spin_unlock_irqrestore(&dev->devres_lock, flags);
 486
 487         /* Release.  Note that both devres and devres_group are
 488          * handled as devres in the following loop.  This is safe.
 489          */
 490         list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
 491                 devres_log(dev, &dr->node, "REL");
 492                 dr->node.release(dev, dr->data);
 493                 kfree(dr);
 494         }
 495
 496         return cnt;
 497 }
 498
 499 /**
 500  * devres_release_all - Release all managed resources
 501  * @dev: Device to release resources for
 502  *
 503  * Release all resources associated with @dev.  This function is
 504  * called on driver detach.
 505  */
 506 int devres_release_all(struct device *dev)
 507 {
 508         unsigned long flags;
 509
 510         /* Looks like an uninitialized device structure */
 511         if (WARN_ON(dev->devres_head.next == NULL))
 512                 return -ENODEV;
 513         spin_lock_irqsave(&dev->devres_lock, flags);
 514         return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
 515                              flags);
 516 }
 517
 518 /**
 519  * devres_open_group - Open a new devres group
 520  * @dev: Device to open devres group for
 521  * @id: Separator ID
 522  * @gfp: Allocation flags
 523  *
 524  * Open a new devres group for @dev with @id.  For @id, using a
 525  * pointer to an object which won't be used for another group is
 526  * recommended.  If @id is NULL, address-wise unique ID is created.
 527  *
 528  * RETURNS:
 529  * ID of the new group, NULL on failure.
 530  */
 531 void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
 532 {
 533         struct devres_group *grp;
 534         unsigned long flags;
 535
 536         grp = kmalloc(sizeof(*grp), gfp);
 537         if (unlikely(!grp))
 538                 return NULL;
 539
 540         grp->node[0].release = &group_open_release;
 541         grp->node[1].release = &group_close_release;
 542         INIT_LIST_HEAD(&grp->node[0].entry);
 543         INIT_LIST_HEAD(&grp->node[1].entry);
 544         set_node_dbginfo(&grp->node[0], "grp<", 0);
 545         set_node_dbginfo(&grp->node[1], "grp>", 0);
 546         grp->id = grp;
 547         if (id)
 548                 grp->id = id;
 549
 550         spin_lock_irqsave(&dev->devres_lock, flags);
 551         add_dr(dev, &grp->node[0]);
 552         spin_unlock_irqrestore(&dev->devres_lock, flags);
 553         return grp->id;
 554 }
 555 EXPORT_SYMBOL_GPL(devres_open_group);
 556
 557 /* Find devres group with ID @id.  If @id is NULL, look for the latest. */
 558 static struct devres_group * find_group(struct device *dev, void *id)
 559 {
 560         struct devres_node *node;
 561
 562         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 563                 struct devres_group *grp;
 564
 565                 if (node->release != &group_open_release)
 566                         continue;
 567
 568                 grp = container_of(node, struct devres_group, node[0]);
 569
 570                 if (id) {
 571                         if (grp->id == id)
 572                                 return grp;
 573                 } else if (list_empty(&grp->node[1].entry))
 574                         return grp;
 575         }
 576
 577         return NULL;
 578 }
 579
 580 /**
 581  * devres_close_group - Close a devres group
 582  * @dev: Device to close devres group for
 583  * @id: ID of target group, can be NULL
 584  *
 585  * Close the group identified by @id.  If @id is NULL, the latest open
 586  * group is selected.
 587  */
 588 void devres_close_group(struct device *dev, void *id)
 589 {
 590         struct devres_group *grp;
 591         unsigned long flags;
 592
 593         spin_lock_irqsave(&dev->devres_lock, flags);
 594
 595         grp = find_group(dev, id);
 596         if (grp)
 597                 add_dr(dev, &grp->node[1]);
 598         else
 599                 WARN_ON(1);
 600
 601         spin_unlock_irqrestore(&dev->devres_lock, flags);
 602 }
 603 EXPORT_SYMBOL_GPL(devres_close_group);
 604
 605 /**
 606  * devres_remove_group - Remove a devres group
 607  * @dev: Device to remove group for
 608  * @id: ID of target group, can be NULL
 609  *
 610  * Remove the group identified by @id.  If @id is NULL, the latest
 611  * open group is selected.  Note that removing a group doesn't affect
 612  * any other resources.
 613  */
 614 void devres_remove_group(struct device *dev, void *id)
 615 {
 616         struct devres_group *grp;
 617         unsigned long flags;
 618
 619         spin_lock_irqsave(&dev->devres_lock, flags);
 620
 621         grp = find_group(dev, id);
 622         if (grp) {
 623                 list_del_init(&grp->node[0].entry);
 624                 list_del_init(&grp->node[1].entry);
 625                 devres_log(dev, &grp->node[0], "REM");
 626         } else
 627                 WARN_ON(1);
 628
 629         spin_unlock_irqrestore(&dev->devres_lock, flags);
 630
 631         kfree(grp);
 632 }
 633 EXPORT_SYMBOL_GPL(devres_remove_group);
 634
 635 /**
 636  * devres_release_group - Release resources in a devres group
 637  * @dev: Device to release group for
 638  * @id: ID of target group, can be NULL
 639  *
 640  * Release all resources in the group identified by @id.  If @id is
 641  * NULL, the latest open group is selected.  The selected group and
 642  * groups properly nested inside the selected group are removed.
 643  *
 644  * RETURNS:
 645  * The number of released non-group resources.
 646  */
 647 int devres_release_group(struct device *dev, void *id)
 648 {
 649         struct devres_group *grp;
 650         unsigned long flags;
 651         int cnt = 0;
 652
 653         spin_lock_irqsave(&dev->devres_lock, flags);
 654
 655         grp = find_group(dev, id);
 656         if (grp) {
 657                 struct list_head *first = &grp->node[0].entry;
 658                 struct list_head *end = &dev->devres_head;
 659
 660                 if (!list_empty(&grp->node[1].entry))
 661                         end = grp->node[1].entry.next;
 662
 663                 cnt = release_nodes(dev, first, end, flags);
 664         } else {
 665                 WARN_ON(1);
 666                 spin_unlock_irqrestore(&dev->devres_lock, flags);
 667         }
 668
 669         return cnt;
 670 }
 671 EXPORT_SYMBOL_GPL(devres_release_group);
 672
 673 /*
 674  * Custom devres actions allow inserting a simple function call
 675  * into the teadown sequence.
 676  */
 677
 678 struct action_devres {
 679         void *data;
 680         void (*action)(void *);
 681 };
 682
 683 static int devm_action_match(struct device *dev, void *res, void *p)
 684 {
 685         struct action_devres *devres = res;
 686         struct action_devres *target = p;
 687
 688         return devres->action == target->action &&
 689                devres->data == target->data;
 690 }
 691
 692 static void devm_action_release(struct device *dev, void *res)
 693 {
 694         struct action_devres *devres = res;
 695
 696         devres->action(devres->data);
 697 }
 698
 699 /**
 700  * devm_add_action() - add a custom action to list of managed resources
 701  * @dev: Device that owns the action
 702  * @action: Function that should be called
 703  * @data: Pointer to data passed to @action implementation
 704  *
 705  * This adds a custom action to the list of managed resources so that
 706  * it gets executed as part of standard resource unwinding.
 707  */
 708 int devm_add_action(struct device *dev, void (*action)(void *), void *data)
 709 {
 710         struct action_devres *devres;
 711
 712         devres = devres_alloc(devm_action_release,
 713                               sizeof(struct action_devres), GFP_KERNEL);
 714         if (!devres)
 715                 return -ENOMEM;
 716
 717         devres->data = data;
 718         devres->action = action;
 719
 720         devres_add(dev, devres);
 721         return 0;
 722 }
 723 EXPORT_SYMBOL_GPL(devm_add_action);
 724
 725 /**
 726  * devm_remove_action() - removes previously added custom action
 727  * @dev: Device that owns the action
 728  * @action: Function implementing the action
 729  * @data: Pointer to data passed to @action implementation
 730  *
 731  * Removes instance of @action previously added by devm_add_action().
 732  * Both action and data should match one of the existing entries.
 733  */
 734 void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
 735 {
 736         struct action_devres devres = {
 737                 .data = data,
 738                 .action = action,
 739         };
 740
 741         WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
 742                                &devres));
 743
 744 }
 745 EXPORT_SYMBOL_GPL(devm_remove_action);
 746
 747 /*
 748  * Managed kzalloc/kfree
 749  */
 750 static void devm_kzalloc_release(struct device *dev, void *res)
 751 {
 752         /* noop */
 753 }
 754
 755 static int devm_kzalloc_match(struct device *dev, void *res, void *data)
 756 {
 757         return res == data;
 758 }
 759
 760 /**
 761  * devm_kzalloc - Resource-managed kzalloc
 762  * @dev: Device to allocate memory for
 763  * @size: Allocation size
 764  * @gfp: Allocation gfp flags
 765  *
 766  * Managed kzalloc.  Memory allocated with this function is
 767  * automatically freed on driver detach.  Like all other devres
 768  * resources, guaranteed alignment is unsigned long long.
 769  *
 770  * RETURNS:
 771  * Pointer to allocated memory on success, NULL on failure.
 772  */
 773 void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
 774 {
 775         struct devres *dr;
 776
 777         /* use raw alloc_dr for kmalloc caller tracing */
 778         dr = alloc_dr(devm_kzalloc_release, size, gfp);
 779         if (unlikely(!dr))
 780                 return NULL;
 781
 782         set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
 783         devres_add(dev, dr->data);
 784         return dr->data;
 785 }
 786 EXPORT_SYMBOL_GPL(devm_kzalloc);
 787
 788 /**
 789  * devm_kfree - Resource-managed kfree
 790  * @dev: Device this memory belongs to
 791  * @p: Memory to free
 792  *
 793  * Free memory allocated with devm_kzalloc().
 794  */
 795 void devm_kfree(struct device *dev, void *p)
 796 {
 797         int rc;
 798
 799         rc = devres_destroy(dev, devm_kzalloc_release, devm_kzalloc_match, p);
 800         WARN_ON(rc);
 801 }
 802 EXPORT_SYMBOL_GPL(devm_kfree);