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_printk(KERN_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_free - Free device resource data
 148  * @res: Pointer to devres data to free
 149  *
 150  * Free devres created with devres_alloc().
 151  */
 152 void devres_free(void *res)
 153 {
 154         if (res) {
 155                 struct devres *dr = container_of(res, struct devres, data);
 156
 157                 BUG_ON(!list_empty(&dr->node.entry));
 158                 kfree(dr);
 159         }
 160 }
 161 EXPORT_SYMBOL_GPL(devres_free);
 162
 163 /**
 164  * devres_add - Register device resource
 165  * @dev: Device to add resource to
 166  * @res: Resource to register
 167  *
 168  * Register devres @res to @dev.  @res should have been allocated
 169  * using devres_alloc().  On driver detach, the associated release
 170  * function will be invoked and devres will be freed automatically.
 171  */
 172 void devres_add(struct device *dev, void *res)
 173 {
 174         struct devres *dr = container_of(res, struct devres, data);
 175         unsigned long flags;
 176
 177         spin_lock_irqsave(&dev->devres_lock, flags);
 178         add_dr(dev, &dr->node);
 179         spin_unlock_irqrestore(&dev->devres_lock, flags);
 180 }
 181 EXPORT_SYMBOL_GPL(devres_add);
 182
 183 static struct devres *find_dr(struct device *dev, dr_release_t release,
 184                               dr_match_t match, void *match_data)
 185 {
 186         struct devres_node *node;
 187
 188         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 189                 struct devres *dr = container_of(node, struct devres, node);
 190
 191                 if (node->release != release)
 192                         continue;
 193                 if (match && !match(dev, dr->data, match_data))
 194                         continue;
 195                 return dr;
 196         }
 197
 198         return NULL;
 199 }
 200
 201 /**
 202  * devres_find - Find device resource
 203  * @dev: Device to lookup resource from
 204  * @release: Look for resources associated with this release function
 205  * @match: Match function (optional)
 206  * @match_data: Data for the match function
 207  *
 208  * Find the latest devres of @dev which is associated with @release
 209  * and for which @match returns 1.  If @match is NULL, it's considered
 210  * to match all.
 211  *
 212  * RETURNS:
 213  * Pointer to found devres, NULL if not found.
 214  */
 215 void * devres_find(struct device *dev, dr_release_t release,
 216                    dr_match_t match, void *match_data)
 217 {
 218         struct devres *dr;
 219         unsigned long flags;
 220
 221         spin_lock_irqsave(&dev->devres_lock, flags);
 222         dr = find_dr(dev, release, match, match_data);
 223         spin_unlock_irqrestore(&dev->devres_lock, flags);
 224
 225         if (dr)
 226                 return dr->data;
 227         return NULL;
 228 }
 229 EXPORT_SYMBOL_GPL(devres_find);
 230
 231 /**
 232  * devres_get - Find devres, if non-existent, add one atomically
 233  * @dev: Device to lookup or add devres for
 234  * @new_res: Pointer to new initialized devres to add if not found
 235  * @match: Match function (optional)
 236  * @match_data: Data for the match function
 237  *
 238  * Find the latest devres of @dev which has the same release function
 239  * as @new_res and for which @match return 1.  If found, @new_res is
 240  * freed; otherwise, @new_res is added atomically.
 241  *
 242  * RETURNS:
 243  * Pointer to found or added devres.
 244  */
 245 void * devres_get(struct device *dev, void *new_res,
 246                   dr_match_t match, void *match_data)
 247 {
 248         struct devres *new_dr = container_of(new_res, struct devres, data);
 249         struct devres *dr;
 250         unsigned long flags;
 251
 252         spin_lock_irqsave(&dev->devres_lock, flags);
 253         dr = find_dr(dev, new_dr->node.release, match, match_data);
 254         if (!dr) {
 255                 add_dr(dev, &new_dr->node);
 256                 dr = new_dr;
 257                 new_dr = NULL;
 258         }
 259         spin_unlock_irqrestore(&dev->devres_lock, flags);
 260         devres_free(new_dr);
 261
 262         return dr->data;
 263 }
 264 EXPORT_SYMBOL_GPL(devres_get);
 265
 266 /**
 267  * devres_remove - Find a device resource and remove it
 268  * @dev: Device to find resource from
 269  * @release: Look for resources associated with this release function
 270  * @match: Match function (optional)
 271  * @match_data: Data for the match function
 272  *
 273  * Find the latest devres of @dev associated with @release and for
 274  * which @match returns 1.  If @match is NULL, it's considered to
 275  * match all.  If found, the resource is removed atomically and
 276  * returned.
 277  *
 278  * RETURNS:
 279  * Pointer to removed devres on success, NULL if not found.
 280  */
 281 void * devres_remove(struct device *dev, dr_release_t release,
 282                      dr_match_t match, void *match_data)
 283 {
 284         struct devres *dr;
 285         unsigned long flags;
 286
 287         spin_lock_irqsave(&dev->devres_lock, flags);
 288         dr = find_dr(dev, release, match, match_data);
 289         if (dr) {
 290                 list_del_init(&dr->node.entry);
 291                 devres_log(dev, &dr->node, "REM");
 292         }
 293         spin_unlock_irqrestore(&dev->devres_lock, flags);
 294
 295         if (dr)
 296                 return dr->data;
 297         return NULL;
 298 }
 299 EXPORT_SYMBOL_GPL(devres_remove);
 300
 301 /**
 302  * devres_destroy - Find a device resource and destroy it
 303  * @dev: Device to find resource from
 304  * @release: Look for resources associated with this release function
 305  * @match: Match function (optional)
 306  * @match_data: Data for the match function
 307  *
 308  * Find the latest devres of @dev associated with @release and for
 309  * which @match returns 1.  If @match is NULL, it's considered to
 310  * match all.  If found, the resource is removed atomically and freed.
 311  *
 312  * RETURNS:
 313  * 0 if devres is found and freed, -ENOENT if not found.
 314  */
 315 int devres_destroy(struct device *dev, dr_release_t release,
 316                    dr_match_t match, void *match_data)
 317 {
 318         void *res;
 319
 320         res = devres_remove(dev, release, match, match_data);
 321         if (unlikely(!res))
 322                 return -ENOENT;
 323
 324         devres_free(res);
 325         return 0;
 326 }
 327 EXPORT_SYMBOL_GPL(devres_destroy);
 328
 329 static int remove_nodes(struct device *dev,
 330                         struct list_head *first, struct list_head *end,
 331                         struct list_head *todo)
 332 {
 333         int cnt = 0, nr_groups = 0;
 334         struct list_head *cur;
 335
 336         /* First pass - move normal devres entries to @todo and clear
 337          * devres_group colors.
 338          */
 339         cur = first;
 340         while (cur != end) {
 341                 struct devres_node *node;
 342                 struct devres_group *grp;
 343
 344                 node = list_entry(cur, struct devres_node, entry);
 345                 cur = cur->next;
 346
 347                 grp = node_to_group(node);
 348                 if (grp) {
 349                         /* clear color of group markers in the first pass */
 350                         grp->color = 0;
 351                         nr_groups++;
 352                 } else {
 353                         /* regular devres entry */
 354                         if (&node->entry == first)
 355                                 first = first->next;
 356                         list_move_tail(&node->entry, todo);
 357                         cnt++;
 358                 }
 359         }
 360
 361         if (!nr_groups)
 362                 return cnt;
 363
 364         /* Second pass - Scan groups and color them.  A group gets
 365          * color value of two iff the group is wholly contained in
 366          * [cur, end).  That is, for a closed group, both opening and
 367          * closing markers should be in the range, while just the
 368          * opening marker is enough for an open group.
 369          */
 370         cur = first;
 371         while (cur != end) {
 372                 struct devres_node *node;
 373                 struct devres_group *grp;
 374
 375                 node = list_entry(cur, struct devres_node, entry);
 376                 cur = cur->next;
 377
 378                 grp = node_to_group(node);
 379                 BUG_ON(!grp || list_empty(&grp->node[0].entry));
 380
 381                 grp->color++;
 382                 if (list_empty(&grp->node[1].entry))
 383                         grp->color++;
 384
 385                 BUG_ON(grp->color <= 0 || grp->color > 2);
 386                 if (grp->color == 2) {
 387                         /* No need to update cur or end.  The removed
 388                          * nodes are always before both.
 389                          */
 390                         list_move_tail(&grp->node[0].entry, todo);
 391                         list_del_init(&grp->node[1].entry);
 392                 }
 393         }
 394
 395         return cnt;
 396 }
 397
 398 static int release_nodes(struct device *dev, struct list_head *first,
 399                          struct list_head *end, unsigned long flags)
 400 {
 401         LIST_HEAD(todo);
 402         int cnt;
 403         struct devres *dr, *tmp;
 404
 405         cnt = remove_nodes(dev, first, end, &todo);
 406
 407         spin_unlock_irqrestore(&dev->devres_lock, flags);
 408
 409         /* Release.  Note that both devres and devres_group are
 410          * handled as devres in the following loop.  This is safe.
 411          */
 412         list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
 413                 devres_log(dev, &dr->node, "REL");
 414                 dr->node.release(dev, dr->data);
 415                 kfree(dr);
 416         }
 417
 418         return cnt;
 419 }
 420
 421 /**
 422  * devres_release_all - Release all managed resources
 423  * @dev: Device to release resources for
 424  *
 425  * Release all resources associated with @dev.  This function is
 426  * called on driver detach.
 427  */
 428 int devres_release_all(struct device *dev)
 429 {
 430         unsigned long flags;
 431
 432         /* Looks like an uninitialized device structure */
 433         if (WARN_ON(dev->devres_head.next == NULL))
 434                 return -ENODEV;
 435         spin_lock_irqsave(&dev->devres_lock, flags);
 436         return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
 437                              flags);
 438 }
 439
 440 /**
 441  * devres_open_group - Open a new devres group
 442  * @dev: Device to open devres group for
 443  * @id: Separator ID
 444  * @gfp: Allocation flags
 445  *
 446  * Open a new devres group for @dev with @id.  For @id, using a
 447  * pointer to an object which won't be used for another group is
 448  * recommended.  If @id is NULL, address-wise unique ID is created.
 449  *
 450  * RETURNS:
 451  * ID of the new group, NULL on failure.
 452  */
 453 void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
 454 {
 455         struct devres_group *grp;
 456         unsigned long flags;
 457
 458         grp = kmalloc(sizeof(*grp), gfp);
 459         if (unlikely(!grp))
 460                 return NULL;
 461
 462         grp->node[0].release = &group_open_release;
 463         grp->node[1].release = &group_close_release;
 464         INIT_LIST_HEAD(&grp->node[0].entry);
 465         INIT_LIST_HEAD(&grp->node[1].entry);
 466         set_node_dbginfo(&grp->node[0], "grp<", 0);
 467         set_node_dbginfo(&grp->node[1], "grp>", 0);
 468         grp->id = grp;
 469         if (id)
 470                 grp->id = id;
 471
 472         spin_lock_irqsave(&dev->devres_lock, flags);
 473         add_dr(dev, &grp->node[0]);
 474         spin_unlock_irqrestore(&dev->devres_lock, flags);
 475         return grp->id;
 476 }
 477 EXPORT_SYMBOL_GPL(devres_open_group);
 478
 479 /* Find devres group with ID @id.  If @id is NULL, look for the latest. */
 480 static struct devres_group * find_group(struct device *dev, void *id)
 481 {
 482         struct devres_node *node;
 483
 484         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 485                 struct devres_group *grp;
 486
 487                 if (node->release != &group_open_release)
 488                         continue;
 489
 490                 grp = container_of(node, struct devres_group, node[0]);
 491
 492                 if (id) {
 493                         if (grp->id == id)
 494                                 return grp;
 495                 } else if (list_empty(&grp->node[1].entry))
 496                         return grp;
 497         }
 498
 499         return NULL;
 500 }
 501
 502 /**
 503  * devres_close_group - Close a devres group
 504  * @dev: Device to close devres group for
 505  * @id: ID of target group, can be NULL
 506  *
 507  * Close the group identified by @id.  If @id is NULL, the latest open
 508  * group is selected.
 509  */
 510 void devres_close_group(struct device *dev, void *id)
 511 {
 512         struct devres_group *grp;
 513         unsigned long flags;
 514
 515         spin_lock_irqsave(&dev->devres_lock, flags);
 516
 517         grp = find_group(dev, id);
 518         if (grp)
 519                 add_dr(dev, &grp->node[1]);
 520         else
 521                 WARN_ON(1);
 522
 523         spin_unlock_irqrestore(&dev->devres_lock, flags);
 524 }
 525 EXPORT_SYMBOL_GPL(devres_close_group);
 526
 527 /**
 528  * devres_remove_group - Remove a devres group
 529  * @dev: Device to remove group for
 530  * @id: ID of target group, can be NULL
 531  *
 532  * Remove the group identified by @id.  If @id is NULL, the latest
 533  * open group is selected.  Note that removing a group doesn't affect
 534  * any other resources.
 535  */
 536 void devres_remove_group(struct device *dev, void *id)
 537 {
 538         struct devres_group *grp;
 539         unsigned long flags;
 540
 541         spin_lock_irqsave(&dev->devres_lock, flags);
 542
 543         grp = find_group(dev, id);
 544         if (grp) {
 545                 list_del_init(&grp->node[0].entry);
 546                 list_del_init(&grp->node[1].entry);
 547                 devres_log(dev, &grp->node[0], "REM");
 548         } else
 549                 WARN_ON(1);
 550
 551         spin_unlock_irqrestore(&dev->devres_lock, flags);
 552
 553         kfree(grp);
 554 }
 555 EXPORT_SYMBOL_GPL(devres_remove_group);
 556
 557 /**
 558  * devres_release_group - Release resources in a devres group
 559  * @dev: Device to release group for
 560  * @id: ID of target group, can be NULL
 561  *
 562  * Release all resources in the group identified by @id.  If @id is
 563  * NULL, the latest open group is selected.  The selected group and
 564  * groups properly nested inside the selected group are removed.
 565  *
 566  * RETURNS:
 567  * The number of released non-group resources.
 568  */
 569 int devres_release_group(struct device *dev, void *id)
 570 {
 571         struct devres_group *grp;
 572         unsigned long flags;
 573         int cnt = 0;
 574
 575         spin_lock_irqsave(&dev->devres_lock, flags);
 576
 577         grp = find_group(dev, id);
 578         if (grp) {
 579                 struct list_head *first = &grp->node[0].entry;
 580                 struct list_head *end = &dev->devres_head;
 581
 582                 if (!list_empty(&grp->node[1].entry))
 583                         end = grp->node[1].entry.next;
 584
 585                 cnt = release_nodes(dev, first, end, flags);
 586         } else {
 587                 WARN_ON(1);
 588                 spin_unlock_irqrestore(&dev->devres_lock, flags);
 589         }
 590
 591         return cnt;
 592 }
 593 EXPORT_SYMBOL_GPL(devres_release_group);
 594
 595 /*
 596  * Managed kzalloc/kfree
 597  */
 598 static void devm_kzalloc_release(struct device *dev, void *res)
 599 {
 600         /* noop */
 601 }
 602
 603 static int devm_kzalloc_match(struct device *dev, void *res, void *data)
 604 {
 605         return res == data;
 606 }
 607
 608 /**
 609  * devm_kzalloc - Resource-managed kzalloc
 610  * @dev: Device to allocate memory for
 611  * @size: Allocation size
 612  * @gfp: Allocation gfp flags
 613  *
 614  * Managed kzalloc.  Memory allocated with this function is
 615  * automatically freed on driver detach.  Like all other devres
 616  * resources, guaranteed alignment is unsigned long long.
 617  *
 618  * RETURNS:
 619  * Pointer to allocated memory on success, NULL on failure.
 620  */
 621 void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
 622 {
 623         struct devres *dr;
 624
 625         /* use raw alloc_dr for kmalloc caller tracing */
 626         dr = alloc_dr(devm_kzalloc_release, size, gfp);
 627         if (unlikely(!dr))
 628                 return NULL;
 629
 630         set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
 631         devres_add(dev, dr->data);
 632         return dr->data;
 633 }
 634 EXPORT_SYMBOL_GPL(devm_kzalloc);
 635
 636 /**
 637  * devm_kfree - Resource-managed kfree
 638  * @dev: Device this memory belongs to
 639  * @p: Memory to free
 640  *
 641  * Free memory allocated with dev_kzalloc().
 642  */
 643 void devm_kfree(struct device *dev, void *p)
 644 {
 645         int rc;
 646
 647         rc = devres_destroy(dev, devm_kzalloc_release, devm_kzalloc_match, p);
 648         WARN_ON(rc);
 649 }
 650 EXPORT_SYMBOL_GPL(devm_kfree);