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TOMOYO Linux Cross Reference
Linux/kernel/resource.c

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  1 /*
  2  *      linux/kernel/resource.c
  3  *
  4  * Copyright (C) 1999   Linus Torvalds
  5  * Copyright (C) 1999   Martin Mares <mj@ucw.cz>
  6  *
  7  * Arbitrary resource management.
  8  */
  9 
 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 11 
 12 #include <linux/export.h>
 13 #include <linux/errno.h>
 14 #include <linux/ioport.h>
 15 #include <linux/init.h>
 16 #include <linux/slab.h>
 17 #include <linux/spinlock.h>
 18 #include <linux/fs.h>
 19 #include <linux/proc_fs.h>
 20 #include <linux/sched.h>
 21 #include <linux/seq_file.h>
 22 #include <linux/device.h>
 23 #include <linux/pfn.h>
 24 #include <linux/mm.h>
 25 #include <linux/resource_ext.h>
 26 #include <asm/io.h>
 27 
 28 
 29 struct resource ioport_resource = {
 30         .name   = "PCI IO",
 31         .start  = 0,
 32         .end    = IO_SPACE_LIMIT,
 33         .flags  = IORESOURCE_IO,
 34 };
 35 EXPORT_SYMBOL(ioport_resource);
 36 
 37 struct resource iomem_resource = {
 38         .name   = "PCI mem",
 39         .start  = 0,
 40         .end    = -1,
 41         .flags  = IORESOURCE_MEM,
 42 };
 43 EXPORT_SYMBOL(iomem_resource);
 44 
 45 /* constraints to be met while allocating resources */
 46 struct resource_constraint {
 47         resource_size_t min, max, align;
 48         resource_size_t (*alignf)(void *, const struct resource *,
 49                         resource_size_t, resource_size_t);
 50         void *alignf_data;
 51 };
 52 
 53 static DEFINE_RWLOCK(resource_lock);
 54 
 55 /*
 56  * For memory hotplug, there is no way to free resource entries allocated
 57  * by boot mem after the system is up. So for reusing the resource entry
 58  * we need to remember the resource.
 59  */
 60 static struct resource *bootmem_resource_free;
 61 static DEFINE_SPINLOCK(bootmem_resource_lock);
 62 
 63 static struct resource *next_resource(struct resource *p, bool sibling_only)
 64 {
 65         /* Caller wants to traverse through siblings only */
 66         if (sibling_only)
 67                 return p->sibling;
 68 
 69         if (p->child)
 70                 return p->child;
 71         while (!p->sibling && p->parent)
 72                 p = p->parent;
 73         return p->sibling;
 74 }
 75 
 76 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
 77 {
 78         struct resource *p = v;
 79         (*pos)++;
 80         return (void *)next_resource(p, false);
 81 }
 82 
 83 #ifdef CONFIG_PROC_FS
 84 
 85 enum { MAX_IORES_LEVEL = 5 };
 86 
 87 static void *r_start(struct seq_file *m, loff_t *pos)
 88         __acquires(resource_lock)
 89 {
 90         struct resource *p = PDE_DATA(file_inode(m->file));
 91         loff_t l = 0;
 92         read_lock(&resource_lock);
 93         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
 94                 ;
 95         return p;
 96 }
 97 
 98 static void r_stop(struct seq_file *m, void *v)
 99         __releases(resource_lock)
100 {
101         read_unlock(&resource_lock);
102 }
103 
104 static int r_show(struct seq_file *m, void *v)
105 {
106         struct resource *root = PDE_DATA(file_inode(m->file));
107         struct resource *r = v, *p;
108         unsigned long long start, end;
109         int width = root->end < 0x10000 ? 4 : 8;
110         int depth;
111 
112         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
113                 if (p->parent == root)
114                         break;
115 
116         if (file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN)) {
117                 start = r->start;
118                 end = r->end;
119         } else {
120                 start = end = 0;
121         }
122 
123         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
124                         depth * 2, "",
125                         width, start,
126                         width, end,
127                         r->name ? r->name : "<BAD>");
128         return 0;
129 }
130 
131 static const struct seq_operations resource_op = {
132         .start  = r_start,
133         .next   = r_next,
134         .stop   = r_stop,
135         .show   = r_show,
136 };
137 
138 static int __init ioresources_init(void)
139 {
140         proc_create_seq_data("ioports", 0, NULL, &resource_op,
141                         &ioport_resource);
142         proc_create_seq_data("iomem", 0, NULL, &resource_op, &iomem_resource);
143         return 0;
144 }
145 __initcall(ioresources_init);
146 
147 #endif /* CONFIG_PROC_FS */
148 
149 static void free_resource(struct resource *res)
150 {
151         if (!res)
152                 return;
153 
154         if (!PageSlab(virt_to_head_page(res))) {
155                 spin_lock(&bootmem_resource_lock);
156                 res->sibling = bootmem_resource_free;
157                 bootmem_resource_free = res;
158                 spin_unlock(&bootmem_resource_lock);
159         } else {
160                 kfree(res);
161         }
162 }
163 
164 static struct resource *alloc_resource(gfp_t flags)
165 {
166         struct resource *res = NULL;
167 
168         spin_lock(&bootmem_resource_lock);
169         if (bootmem_resource_free) {
170                 res = bootmem_resource_free;
171                 bootmem_resource_free = res->sibling;
172         }
173         spin_unlock(&bootmem_resource_lock);
174 
175         if (res)
176                 memset(res, 0, sizeof(struct resource));
177         else
178                 res = kzalloc(sizeof(struct resource), flags);
179 
180         return res;
181 }
182 
183 /* Return the conflict entry if you can't request it */
184 static struct resource * __request_resource(struct resource *root, struct resource *new)
185 {
186         resource_size_t start = new->start;
187         resource_size_t end = new->end;
188         struct resource *tmp, **p;
189 
190         if (end < start)
191                 return root;
192         if (start < root->start)
193                 return root;
194         if (end > root->end)
195                 return root;
196         p = &root->child;
197         for (;;) {
198                 tmp = *p;
199                 if (!tmp || tmp->start > end) {
200                         new->sibling = tmp;
201                         *p = new;
202                         new->parent = root;
203                         return NULL;
204                 }
205                 p = &tmp->sibling;
206                 if (tmp->end < start)
207                         continue;
208                 return tmp;
209         }
210 }
211 
212 static int __release_resource(struct resource *old, bool release_child)
213 {
214         struct resource *tmp, **p, *chd;
215 
216         p = &old->parent->child;
217         for (;;) {
218                 tmp = *p;
219                 if (!tmp)
220                         break;
221                 if (tmp == old) {
222                         if (release_child || !(tmp->child)) {
223                                 *p = tmp->sibling;
224                         } else {
225                                 for (chd = tmp->child;; chd = chd->sibling) {
226                                         chd->parent = tmp->parent;
227                                         if (!(chd->sibling))
228                                                 break;
229                                 }
230                                 *p = tmp->child;
231                                 chd->sibling = tmp->sibling;
232                         }
233                         old->parent = NULL;
234                         return 0;
235                 }
236                 p = &tmp->sibling;
237         }
238         return -EINVAL;
239 }
240 
241 static void __release_child_resources(struct resource *r)
242 {
243         struct resource *tmp, *p;
244         resource_size_t size;
245 
246         p = r->child;
247         r->child = NULL;
248         while (p) {
249                 tmp = p;
250                 p = p->sibling;
251 
252                 tmp->parent = NULL;
253                 tmp->sibling = NULL;
254                 __release_child_resources(tmp);
255 
256                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
257                 /* need to restore size, and keep flags */
258                 size = resource_size(tmp);
259                 tmp->start = 0;
260                 tmp->end = size - 1;
261         }
262 }
263 
264 void release_child_resources(struct resource *r)
265 {
266         write_lock(&resource_lock);
267         __release_child_resources(r);
268         write_unlock(&resource_lock);
269 }
270 
271 /**
272  * request_resource_conflict - request and reserve an I/O or memory resource
273  * @root: root resource descriptor
274  * @new: resource descriptor desired by caller
275  *
276  * Returns 0 for success, conflict resource on error.
277  */
278 struct resource *request_resource_conflict(struct resource *root, struct resource *new)
279 {
280         struct resource *conflict;
281 
282         write_lock(&resource_lock);
283         conflict = __request_resource(root, new);
284         write_unlock(&resource_lock);
285         return conflict;
286 }
287 
288 /**
289  * request_resource - request and reserve an I/O or memory resource
290  * @root: root resource descriptor
291  * @new: resource descriptor desired by caller
292  *
293  * Returns 0 for success, negative error code on error.
294  */
295 int request_resource(struct resource *root, struct resource *new)
296 {
297         struct resource *conflict;
298 
299         conflict = request_resource_conflict(root, new);
300         return conflict ? -EBUSY : 0;
301 }
302 
303 EXPORT_SYMBOL(request_resource);
304 
305 /**
306  * release_resource - release a previously reserved resource
307  * @old: resource pointer
308  */
309 int release_resource(struct resource *old)
310 {
311         int retval;
312 
313         write_lock(&resource_lock);
314         retval = __release_resource(old, true);
315         write_unlock(&resource_lock);
316         return retval;
317 }
318 
319 EXPORT_SYMBOL(release_resource);
320 
321 /**
322  * Finds the lowest iomem resource that covers part of [@start..@end].  The
323  * caller must specify @start, @end, @flags, and @desc (which may be
324  * IORES_DESC_NONE).
325  *
326  * If a resource is found, returns 0 and @*res is overwritten with the part
327  * of the resource that's within [@start..@end]; if none is found, returns
328  * -1 or -EINVAL for other invalid parameters.
329  *
330  * This function walks the whole tree and not just first level children
331  * unless @first_lvl is true.
332  *
333  * @start:      start address of the resource searched for
334  * @end:        end address of same resource
335  * @flags:      flags which the resource must have
336  * @desc:       descriptor the resource must have
337  * @first_lvl:  walk only the first level children, if set
338  * @res:        return ptr, if resource found
339  */
340 static int find_next_iomem_res(resource_size_t start, resource_size_t end,
341                                unsigned long flags, unsigned long desc,
342                                bool first_lvl, struct resource *res)
343 {
344         struct resource *p;
345 
346         if (!res)
347                 return -EINVAL;
348 
349         if (start >= end)
350                 return -EINVAL;
351 
352         read_lock(&resource_lock);
353 
354         for (p = iomem_resource.child; p; p = next_resource(p, first_lvl)) {
355                 if ((p->flags & flags) != flags)
356                         continue;
357                 if ((desc != IORES_DESC_NONE) && (desc != p->desc))
358                         continue;
359                 if (p->start > end) {
360                         p = NULL;
361                         break;
362                 }
363                 if ((p->end >= start) && (p->start <= end))
364                         break;
365         }
366 
367         read_unlock(&resource_lock);
368         if (!p)
369                 return -1;
370 
371         /* copy data */
372         res->start = max(start, p->start);
373         res->end = min(end, p->end);
374         res->flags = p->flags;
375         res->desc = p->desc;
376         return 0;
377 }
378 
379 static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end,
380                                  unsigned long flags, unsigned long desc,
381                                  bool first_lvl, void *arg,
382                                  int (*func)(struct resource *, void *))
383 {
384         struct resource res;
385         int ret = -1;
386 
387         while (start < end &&
388                !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) {
389                 ret = (*func)(&res, arg);
390                 if (ret)
391                         break;
392 
393                 start = res.end + 1;
394         }
395 
396         return ret;
397 }
398 
399 /**
400  * Walks through iomem resources and calls func() with matching resource
401  * ranges. This walks through whole tree and not just first level children.
402  * All the memory ranges which overlap start,end and also match flags and
403  * desc are valid candidates.
404  *
405  * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
406  * @flags: I/O resource flags
407  * @start: start addr
408  * @end: end addr
409  * @arg: function argument for the callback @func
410  * @func: callback function that is called for each qualifying resource area
411  *
412  * NOTE: For a new descriptor search, define a new IORES_DESC in
413  * <linux/ioport.h> and set it in 'desc' of a target resource entry.
414  */
415 int walk_iomem_res_desc(unsigned long desc, unsigned long flags, u64 start,
416                 u64 end, void *arg, int (*func)(struct resource *, void *))
417 {
418         return __walk_iomem_res_desc(start, end, flags, desc, false, arg, func);
419 }
420 EXPORT_SYMBOL_GPL(walk_iomem_res_desc);
421 
422 /*
423  * This function calls the @func callback against all memory ranges of type
424  * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
425  * Now, this function is only for System RAM, it deals with full ranges and
426  * not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate
427  * ranges.
428  */
429 int walk_system_ram_res(u64 start, u64 end, void *arg,
430                         int (*func)(struct resource *, void *))
431 {
432         unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
433 
434         return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true,
435                                      arg, func);
436 }
437 
438 /*
439  * This function calls the @func callback against all memory ranges, which
440  * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
441  */
442 int walk_mem_res(u64 start, u64 end, void *arg,
443                  int (*func)(struct resource *, void *))
444 {
445         unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY;
446 
447         return __walk_iomem_res_desc(start, end, flags, IORES_DESC_NONE, true,
448                                      arg, func);
449 }
450 
451 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
452 
453 /*
454  * This function calls the @func callback against all memory ranges of type
455  * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
456  * It is to be used only for System RAM.
457  */
458 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
459                           void *arg, int (*func)(unsigned long, unsigned long, void *))
460 {
461         resource_size_t start, end;
462         unsigned long flags;
463         struct resource res;
464         unsigned long pfn, end_pfn;
465         int ret = -1;
466 
467         start = (u64) start_pfn << PAGE_SHIFT;
468         end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
469         flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
470         while (start < end &&
471                !find_next_iomem_res(start, end, flags, IORES_DESC_NONE,
472                                     true, &res)) {
473                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
474                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
475                 if (end_pfn > pfn)
476                         ret = (*func)(pfn, end_pfn - pfn, arg);
477                 if (ret)
478                         break;
479                 start = res.end + 1;
480         }
481         return ret;
482 }
483 
484 #endif
485 
486 static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
487 {
488         return 1;
489 }
490 
491 /*
492  * This generic page_is_ram() returns true if specified address is
493  * registered as System RAM in iomem_resource list.
494  */
495 int __weak page_is_ram(unsigned long pfn)
496 {
497         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
498 }
499 EXPORT_SYMBOL_GPL(page_is_ram);
500 
501 /**
502  * region_intersects() - determine intersection of region with known resources
503  * @start: region start address
504  * @size: size of region
505  * @flags: flags of resource (in iomem_resource)
506  * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
507  *
508  * Check if the specified region partially overlaps or fully eclipses a
509  * resource identified by @flags and @desc (optional with IORES_DESC_NONE).
510  * Return REGION_DISJOINT if the region does not overlap @flags/@desc,
511  * return REGION_MIXED if the region overlaps @flags/@desc and another
512  * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
513  * and no other defined resource. Note that REGION_INTERSECTS is also
514  * returned in the case when the specified region overlaps RAM and undefined
515  * memory holes.
516  *
517  * region_intersect() is used by memory remapping functions to ensure
518  * the user is not remapping RAM and is a vast speed up over walking
519  * through the resource table page by page.
520  */
521 int region_intersects(resource_size_t start, size_t size, unsigned long flags,
522                       unsigned long desc)
523 {
524         resource_size_t end = start + size - 1;
525         int type = 0; int other = 0;
526         struct resource *p;
527 
528         read_lock(&resource_lock);
529         for (p = iomem_resource.child; p ; p = p->sibling) {
530                 bool is_type = (((p->flags & flags) == flags) &&
531                                 ((desc == IORES_DESC_NONE) ||
532                                  (desc == p->desc)));
533 
534                 if (start >= p->start && start <= p->end)
535                         is_type ? type++ : other++;
536                 if (end >= p->start && end <= p->end)
537                         is_type ? type++ : other++;
538                 if (p->start >= start && p->end <= end)
539                         is_type ? type++ : other++;
540         }
541         read_unlock(&resource_lock);
542 
543         if (other == 0)
544                 return type ? REGION_INTERSECTS : REGION_DISJOINT;
545 
546         if (type)
547                 return REGION_MIXED;
548 
549         return REGION_DISJOINT;
550 }
551 EXPORT_SYMBOL_GPL(region_intersects);
552 
553 void __weak arch_remove_reservations(struct resource *avail)
554 {
555 }
556 
557 static resource_size_t simple_align_resource(void *data,
558                                              const struct resource *avail,
559                                              resource_size_t size,
560                                              resource_size_t align)
561 {
562         return avail->start;
563 }
564 
565 static void resource_clip(struct resource *res, resource_size_t min,
566                           resource_size_t max)
567 {
568         if (res->start < min)
569                 res->start = min;
570         if (res->end > max)
571                 res->end = max;
572 }
573 
574 /*
575  * Find empty slot in the resource tree with the given range and
576  * alignment constraints
577  */
578 static int __find_resource(struct resource *root, struct resource *old,
579                          struct resource *new,
580                          resource_size_t  size,
581                          struct resource_constraint *constraint)
582 {
583         struct resource *this = root->child;
584         struct resource tmp = *new, avail, alloc;
585 
586         tmp.start = root->start;
587         /*
588          * Skip past an allocated resource that starts at 0, since the assignment
589          * of this->start - 1 to tmp->end below would cause an underflow.
590          */
591         if (this && this->start == root->start) {
592                 tmp.start = (this == old) ? old->start : this->end + 1;
593                 this = this->sibling;
594         }
595         for(;;) {
596                 if (this)
597                         tmp.end = (this == old) ?  this->end : this->start - 1;
598                 else
599                         tmp.end = root->end;
600 
601                 if (tmp.end < tmp.start)
602                         goto next;
603 
604                 resource_clip(&tmp, constraint->min, constraint->max);
605                 arch_remove_reservations(&tmp);
606 
607                 /* Check for overflow after ALIGN() */
608                 avail.start = ALIGN(tmp.start, constraint->align);
609                 avail.end = tmp.end;
610                 avail.flags = new->flags & ~IORESOURCE_UNSET;
611                 if (avail.start >= tmp.start) {
612                         alloc.flags = avail.flags;
613                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
614                                         size, constraint->align);
615                         alloc.end = alloc.start + size - 1;
616                         if (alloc.start <= alloc.end &&
617                             resource_contains(&avail, &alloc)) {
618                                 new->start = alloc.start;
619                                 new->end = alloc.end;
620                                 return 0;
621                         }
622                 }
623 
624 next:           if (!this || this->end == root->end)
625                         break;
626 
627                 if (this != old)
628                         tmp.start = this->end + 1;
629                 this = this->sibling;
630         }
631         return -EBUSY;
632 }
633 
634 /*
635  * Find empty slot in the resource tree given range and alignment.
636  */
637 static int find_resource(struct resource *root, struct resource *new,
638                         resource_size_t size,
639                         struct resource_constraint  *constraint)
640 {
641         return  __find_resource(root, NULL, new, size, constraint);
642 }
643 
644 /**
645  * reallocate_resource - allocate a slot in the resource tree given range & alignment.
646  *      The resource will be relocated if the new size cannot be reallocated in the
647  *      current location.
648  *
649  * @root: root resource descriptor
650  * @old:  resource descriptor desired by caller
651  * @newsize: new size of the resource descriptor
652  * @constraint: the size and alignment constraints to be met.
653  */
654 static int reallocate_resource(struct resource *root, struct resource *old,
655                                resource_size_t newsize,
656                                struct resource_constraint *constraint)
657 {
658         int err=0;
659         struct resource new = *old;
660         struct resource *conflict;
661 
662         write_lock(&resource_lock);
663 
664         if ((err = __find_resource(root, old, &new, newsize, constraint)))
665                 goto out;
666 
667         if (resource_contains(&new, old)) {
668                 old->start = new.start;
669                 old->end = new.end;
670                 goto out;
671         }
672 
673         if (old->child) {
674                 err = -EBUSY;
675                 goto out;
676         }
677 
678         if (resource_contains(old, &new)) {
679                 old->start = new.start;
680                 old->end = new.end;
681         } else {
682                 __release_resource(old, true);
683                 *old = new;
684                 conflict = __request_resource(root, old);
685                 BUG_ON(conflict);
686         }
687 out:
688         write_unlock(&resource_lock);
689         return err;
690 }
691 
692 
693 /**
694  * allocate_resource - allocate empty slot in the resource tree given range & alignment.
695  *      The resource will be reallocated with a new size if it was already allocated
696  * @root: root resource descriptor
697  * @new: resource descriptor desired by caller
698  * @size: requested resource region size
699  * @min: minimum boundary to allocate
700  * @max: maximum boundary to allocate
701  * @align: alignment requested, in bytes
702  * @alignf: alignment function, optional, called if not NULL
703  * @alignf_data: arbitrary data to pass to the @alignf function
704  */
705 int allocate_resource(struct resource *root, struct resource *new,
706                       resource_size_t size, resource_size_t min,
707                       resource_size_t max, resource_size_t align,
708                       resource_size_t (*alignf)(void *,
709                                                 const struct resource *,
710                                                 resource_size_t,
711                                                 resource_size_t),
712                       void *alignf_data)
713 {
714         int err;
715         struct resource_constraint constraint;
716 
717         if (!alignf)
718                 alignf = simple_align_resource;
719 
720         constraint.min = min;
721         constraint.max = max;
722         constraint.align = align;
723         constraint.alignf = alignf;
724         constraint.alignf_data = alignf_data;
725 
726         if ( new->parent ) {
727                 /* resource is already allocated, try reallocating with
728                    the new constraints */
729                 return reallocate_resource(root, new, size, &constraint);
730         }
731 
732         write_lock(&resource_lock);
733         err = find_resource(root, new, size, &constraint);
734         if (err >= 0 && __request_resource(root, new))
735                 err = -EBUSY;
736         write_unlock(&resource_lock);
737         return err;
738 }
739 
740 EXPORT_SYMBOL(allocate_resource);
741 
742 /**
743  * lookup_resource - find an existing resource by a resource start address
744  * @root: root resource descriptor
745  * @start: resource start address
746  *
747  * Returns a pointer to the resource if found, NULL otherwise
748  */
749 struct resource *lookup_resource(struct resource *root, resource_size_t start)
750 {
751         struct resource *res;
752 
753         read_lock(&resource_lock);
754         for (res = root->child; res; res = res->sibling) {
755                 if (res->start == start)
756                         break;
757         }
758         read_unlock(&resource_lock);
759 
760         return res;
761 }
762 
763 /*
764  * Insert a resource into the resource tree. If successful, return NULL,
765  * otherwise return the conflicting resource (compare to __request_resource())
766  */
767 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
768 {
769         struct resource *first, *next;
770 
771         for (;; parent = first) {
772                 first = __request_resource(parent, new);
773                 if (!first)
774                         return first;
775 
776                 if (first == parent)
777                         return first;
778                 if (WARN_ON(first == new))      /* duplicated insertion */
779                         return first;
780 
781                 if ((first->start > new->start) || (first->end < new->end))
782                         break;
783                 if ((first->start == new->start) && (first->end == new->end))
784                         break;
785         }
786 
787         for (next = first; ; next = next->sibling) {
788                 /* Partial overlap? Bad, and unfixable */
789                 if (next->start < new->start || next->end > new->end)
790                         return next;
791                 if (!next->sibling)
792                         break;
793                 if (next->sibling->start > new->end)
794                         break;
795         }
796 
797         new->parent = parent;
798         new->sibling = next->sibling;
799         new->child = first;
800 
801         next->sibling = NULL;
802         for (next = first; next; next = next->sibling)
803                 next->parent = new;
804 
805         if (parent->child == first) {
806                 parent->child = new;
807         } else {
808                 next = parent->child;
809                 while (next->sibling != first)
810                         next = next->sibling;
811                 next->sibling = new;
812         }
813         return NULL;
814 }
815 
816 /**
817  * insert_resource_conflict - Inserts resource in the resource tree
818  * @parent: parent of the new resource
819  * @new: new resource to insert
820  *
821  * Returns 0 on success, conflict resource if the resource can't be inserted.
822  *
823  * This function is equivalent to request_resource_conflict when no conflict
824  * happens. If a conflict happens, and the conflicting resources
825  * entirely fit within the range of the new resource, then the new
826  * resource is inserted and the conflicting resources become children of
827  * the new resource.
828  *
829  * This function is intended for producers of resources, such as FW modules
830  * and bus drivers.
831  */
832 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
833 {
834         struct resource *conflict;
835 
836         write_lock(&resource_lock);
837         conflict = __insert_resource(parent, new);
838         write_unlock(&resource_lock);
839         return conflict;
840 }
841 
842 /**
843  * insert_resource - Inserts a resource in the resource tree
844  * @parent: parent of the new resource
845  * @new: new resource to insert
846  *
847  * Returns 0 on success, -EBUSY if the resource can't be inserted.
848  *
849  * This function is intended for producers of resources, such as FW modules
850  * and bus drivers.
851  */
852 int insert_resource(struct resource *parent, struct resource *new)
853 {
854         struct resource *conflict;
855 
856         conflict = insert_resource_conflict(parent, new);
857         return conflict ? -EBUSY : 0;
858 }
859 EXPORT_SYMBOL_GPL(insert_resource);
860 
861 /**
862  * insert_resource_expand_to_fit - Insert a resource into the resource tree
863  * @root: root resource descriptor
864  * @new: new resource to insert
865  *
866  * Insert a resource into the resource tree, possibly expanding it in order
867  * to make it encompass any conflicting resources.
868  */
869 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
870 {
871         if (new->parent)
872                 return;
873 
874         write_lock(&resource_lock);
875         for (;;) {
876                 struct resource *conflict;
877 
878                 conflict = __insert_resource(root, new);
879                 if (!conflict)
880                         break;
881                 if (conflict == root)
882                         break;
883 
884                 /* Ok, expand resource to cover the conflict, then try again .. */
885                 if (conflict->start < new->start)
886                         new->start = conflict->start;
887                 if (conflict->end > new->end)
888                         new->end = conflict->end;
889 
890                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
891         }
892         write_unlock(&resource_lock);
893 }
894 
895 /**
896  * remove_resource - Remove a resource in the resource tree
897  * @old: resource to remove
898  *
899  * Returns 0 on success, -EINVAL if the resource is not valid.
900  *
901  * This function removes a resource previously inserted by insert_resource()
902  * or insert_resource_conflict(), and moves the children (if any) up to
903  * where they were before.  insert_resource() and insert_resource_conflict()
904  * insert a new resource, and move any conflicting resources down to the
905  * children of the new resource.
906  *
907  * insert_resource(), insert_resource_conflict() and remove_resource() are
908  * intended for producers of resources, such as FW modules and bus drivers.
909  */
910 int remove_resource(struct resource *old)
911 {
912         int retval;
913 
914         write_lock(&resource_lock);
915         retval = __release_resource(old, false);
916         write_unlock(&resource_lock);
917         return retval;
918 }
919 EXPORT_SYMBOL_GPL(remove_resource);
920 
921 static int __adjust_resource(struct resource *res, resource_size_t start,
922                                 resource_size_t size)
923 {
924         struct resource *tmp, *parent = res->parent;
925         resource_size_t end = start + size - 1;
926         int result = -EBUSY;
927 
928         if (!parent)
929                 goto skip;
930 
931         if ((start < parent->start) || (end > parent->end))
932                 goto out;
933 
934         if (res->sibling && (res->sibling->start <= end))
935                 goto out;
936 
937         tmp = parent->child;
938         if (tmp != res) {
939                 while (tmp->sibling != res)
940                         tmp = tmp->sibling;
941                 if (start <= tmp->end)
942                         goto out;
943         }
944 
945 skip:
946         for (tmp = res->child; tmp; tmp = tmp->sibling)
947                 if ((tmp->start < start) || (tmp->end > end))
948                         goto out;
949 
950         res->start = start;
951         res->end = end;
952         result = 0;
953 
954  out:
955         return result;
956 }
957 
958 /**
959  * adjust_resource - modify a resource's start and size
960  * @res: resource to modify
961  * @start: new start value
962  * @size: new size
963  *
964  * Given an existing resource, change its start and size to match the
965  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
966  * Existing children of the resource are assumed to be immutable.
967  */
968 int adjust_resource(struct resource *res, resource_size_t start,
969                     resource_size_t size)
970 {
971         int result;
972 
973         write_lock(&resource_lock);
974         result = __adjust_resource(res, start, size);
975         write_unlock(&resource_lock);
976         return result;
977 }
978 EXPORT_SYMBOL(adjust_resource);
979 
980 static void __init
981 __reserve_region_with_split(struct resource *root, resource_size_t start,
982                             resource_size_t end, const char *name)
983 {
984         struct resource *parent = root;
985         struct resource *conflict;
986         struct resource *res = alloc_resource(GFP_ATOMIC);
987         struct resource *next_res = NULL;
988         int type = resource_type(root);
989 
990         if (!res)
991                 return;
992 
993         res->name = name;
994         res->start = start;
995         res->end = end;
996         res->flags = type | IORESOURCE_BUSY;
997         res->desc = IORES_DESC_NONE;
998 
999         while (1) {
1000 
1001                 conflict = __request_resource(parent, res);
1002                 if (!conflict) {
1003                         if (!next_res)
1004                                 break;
1005                         res = next_res;
1006                         next_res = NULL;
1007                         continue;
1008                 }
1009 
1010                 /* conflict covered whole area */
1011                 if (conflict->start <= res->start &&
1012                                 conflict->end >= res->end) {
1013                         free_resource(res);
1014                         WARN_ON(next_res);
1015                         break;
1016                 }
1017 
1018                 /* failed, split and try again */
1019                 if (conflict->start > res->start) {
1020                         end = res->end;
1021                         res->end = conflict->start - 1;
1022                         if (conflict->end < end) {
1023                                 next_res = alloc_resource(GFP_ATOMIC);
1024                                 if (!next_res) {
1025                                         free_resource(res);
1026                                         break;
1027                                 }
1028                                 next_res->name = name;
1029                                 next_res->start = conflict->end + 1;
1030                                 next_res->end = end;
1031                                 next_res->flags = type | IORESOURCE_BUSY;
1032                                 next_res->desc = IORES_DESC_NONE;
1033                         }
1034                 } else {
1035                         res->start = conflict->end + 1;
1036                 }
1037         }
1038 
1039 }
1040 
1041 void __init
1042 reserve_region_with_split(struct resource *root, resource_size_t start,
1043                           resource_size_t end, const char *name)
1044 {
1045         int abort = 0;
1046 
1047         write_lock(&resource_lock);
1048         if (root->start > start || root->end < end) {
1049                 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
1050                        (unsigned long long)start, (unsigned long long)end,
1051                        root);
1052                 if (start > root->end || end < root->start)
1053                         abort = 1;
1054                 else {
1055                         if (end > root->end)
1056                                 end = root->end;
1057                         if (start < root->start)
1058                                 start = root->start;
1059                         pr_err("fixing request to [0x%llx-0x%llx]\n",
1060                                (unsigned long long)start,
1061                                (unsigned long long)end);
1062                 }
1063                 dump_stack();
1064         }
1065         if (!abort)
1066                 __reserve_region_with_split(root, start, end, name);
1067         write_unlock(&resource_lock);
1068 }
1069 
1070 /**
1071  * resource_alignment - calculate resource's alignment
1072  * @res: resource pointer
1073  *
1074  * Returns alignment on success, 0 (invalid alignment) on failure.
1075  */
1076 resource_size_t resource_alignment(struct resource *res)
1077 {
1078         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
1079         case IORESOURCE_SIZEALIGN:
1080                 return resource_size(res);
1081         case IORESOURCE_STARTALIGN:
1082                 return res->start;
1083         default:
1084                 return 0;
1085         }
1086 }
1087 
1088 /*
1089  * This is compatibility stuff for IO resources.
1090  *
1091  * Note how this, unlike the above, knows about
1092  * the IO flag meanings (busy etc).
1093  *
1094  * request_region creates a new busy region.
1095  *
1096  * release_region releases a matching busy region.
1097  */
1098 
1099 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
1100 
1101 /**
1102  * __request_region - create a new busy resource region
1103  * @parent: parent resource descriptor
1104  * @start: resource start address
1105  * @n: resource region size
1106  * @name: reserving caller's ID string
1107  * @flags: IO resource flags
1108  */
1109 struct resource * __request_region(struct resource *parent,
1110                                    resource_size_t start, resource_size_t n,
1111                                    const char *name, int flags)
1112 {
1113         DECLARE_WAITQUEUE(wait, current);
1114         struct resource *res = alloc_resource(GFP_KERNEL);
1115 
1116         if (!res)
1117                 return NULL;
1118 
1119         res->name = name;
1120         res->start = start;
1121         res->end = start + n - 1;
1122 
1123         write_lock(&resource_lock);
1124 
1125         for (;;) {
1126                 struct resource *conflict;
1127 
1128                 res->flags = resource_type(parent) | resource_ext_type(parent);
1129                 res->flags |= IORESOURCE_BUSY | flags;
1130                 res->desc = parent->desc;
1131 
1132                 conflict = __request_resource(parent, res);
1133                 if (!conflict)
1134                         break;
1135                 if (conflict != parent) {
1136                         if (!(conflict->flags & IORESOURCE_BUSY)) {
1137                                 parent = conflict;
1138                                 continue;
1139                         }
1140                 }
1141                 if (conflict->flags & flags & IORESOURCE_MUXED) {
1142                         add_wait_queue(&muxed_resource_wait, &wait);
1143                         write_unlock(&resource_lock);
1144                         set_current_state(TASK_UNINTERRUPTIBLE);
1145                         schedule();
1146                         remove_wait_queue(&muxed_resource_wait, &wait);
1147                         write_lock(&resource_lock);
1148                         continue;
1149                 }
1150                 /* Uhhuh, that didn't work out.. */
1151                 free_resource(res);
1152                 res = NULL;
1153                 break;
1154         }
1155         write_unlock(&resource_lock);
1156         return res;
1157 }
1158 EXPORT_SYMBOL(__request_region);
1159 
1160 /**
1161  * __release_region - release a previously reserved resource region
1162  * @parent: parent resource descriptor
1163  * @start: resource start address
1164  * @n: resource region size
1165  *
1166  * The described resource region must match a currently busy region.
1167  */
1168 void __release_region(struct resource *parent, resource_size_t start,
1169                       resource_size_t n)
1170 {
1171         struct resource **p;
1172         resource_size_t end;
1173 
1174         p = &parent->child;
1175         end = start + n - 1;
1176 
1177         write_lock(&resource_lock);
1178 
1179         for (;;) {
1180                 struct resource *res = *p;
1181 
1182                 if (!res)
1183                         break;
1184                 if (res->start <= start && res->end >= end) {
1185                         if (!(res->flags & IORESOURCE_BUSY)) {
1186                                 p = &res->child;
1187                                 continue;
1188                         }
1189                         if (res->start != start || res->end != end)
1190                                 break;
1191                         *p = res->sibling;
1192                         write_unlock(&resource_lock);
1193                         if (res->flags & IORESOURCE_MUXED)
1194                                 wake_up(&muxed_resource_wait);
1195                         free_resource(res);
1196                         return;
1197                 }
1198                 p = &res->sibling;
1199         }
1200 
1201         write_unlock(&resource_lock);
1202 
1203         printk(KERN_WARNING "Trying to free nonexistent resource "
1204                 "<%016llx-%016llx>\n", (unsigned long long)start,
1205                 (unsigned long long)end);
1206 }
1207 EXPORT_SYMBOL(__release_region);
1208 
1209 #ifdef CONFIG_MEMORY_HOTREMOVE
1210 /**
1211  * release_mem_region_adjustable - release a previously reserved memory region
1212  * @parent: parent resource descriptor
1213  * @start: resource start address
1214  * @size: resource region size
1215  *
1216  * This interface is intended for memory hot-delete.  The requested region
1217  * is released from a currently busy memory resource.  The requested region
1218  * must either match exactly or fit into a single busy resource entry.  In
1219  * the latter case, the remaining resource is adjusted accordingly.
1220  * Existing children of the busy memory resource must be immutable in the
1221  * request.
1222  *
1223  * Note:
1224  * - Additional release conditions, such as overlapping region, can be
1225  *   supported after they are confirmed as valid cases.
1226  * - When a busy memory resource gets split into two entries, the code
1227  *   assumes that all children remain in the lower address entry for
1228  *   simplicity.  Enhance this logic when necessary.
1229  */
1230 int release_mem_region_adjustable(struct resource *parent,
1231                                   resource_size_t start, resource_size_t size)
1232 {
1233         struct resource **p;
1234         struct resource *res;
1235         struct resource *new_res;
1236         resource_size_t end;
1237         int ret = -EINVAL;
1238 
1239         end = start + size - 1;
1240         if ((start < parent->start) || (end > parent->end))
1241                 return ret;
1242 
1243         /* The alloc_resource() result gets checked later */
1244         new_res = alloc_resource(GFP_KERNEL);
1245 
1246         p = &parent->child;
1247         write_lock(&resource_lock);
1248 
1249         while ((res = *p)) {
1250                 if (res->start >= end)
1251                         break;
1252 
1253                 /* look for the next resource if it does not fit into */
1254                 if (res->start > start || res->end < end) {
1255                         p = &res->sibling;
1256                         continue;
1257                 }
1258 
1259                 if (!(res->flags & IORESOURCE_MEM))
1260                         break;
1261 
1262                 if (!(res->flags & IORESOURCE_BUSY)) {
1263                         p = &res->child;
1264                         continue;
1265                 }
1266 
1267                 /* found the target resource; let's adjust accordingly */
1268                 if (res->start == start && res->end == end) {
1269                         /* free the whole entry */
1270                         *p = res->sibling;
1271                         free_resource(res);
1272                         ret = 0;
1273                 } else if (res->start == start && res->end != end) {
1274                         /* adjust the start */
1275                         ret = __adjust_resource(res, end + 1,
1276                                                 res->end - end);
1277                 } else if (res->start != start && res->end == end) {
1278                         /* adjust the end */
1279                         ret = __adjust_resource(res, res->start,
1280                                                 start - res->start);
1281                 } else {
1282                         /* split into two entries */
1283                         if (!new_res) {
1284                                 ret = -ENOMEM;
1285                                 break;
1286                         }
1287                         new_res->name = res->name;
1288                         new_res->start = end + 1;
1289                         new_res->end = res->end;
1290                         new_res->flags = res->flags;
1291                         new_res->desc = res->desc;
1292                         new_res->parent = res->parent;
1293                         new_res->sibling = res->sibling;
1294                         new_res->child = NULL;
1295 
1296                         ret = __adjust_resource(res, res->start,
1297                                                 start - res->start);
1298                         if (ret)
1299                                 break;
1300                         res->sibling = new_res;
1301                         new_res = NULL;
1302                 }
1303 
1304                 break;
1305         }
1306 
1307         write_unlock(&resource_lock);
1308         free_resource(new_res);
1309         return ret;
1310 }
1311 #endif  /* CONFIG_MEMORY_HOTREMOVE */
1312 
1313 /*
1314  * Managed region resource
1315  */
1316 static void devm_resource_release(struct device *dev, void *ptr)
1317 {
1318         struct resource **r = ptr;
1319 
1320         release_resource(*r);
1321 }
1322 
1323 /**
1324  * devm_request_resource() - request and reserve an I/O or memory resource
1325  * @dev: device for which to request the resource
1326  * @root: root of the resource tree from which to request the resource
1327  * @new: descriptor of the resource to request
1328  *
1329  * This is a device-managed version of request_resource(). There is usually
1330  * no need to release resources requested by this function explicitly since
1331  * that will be taken care of when the device is unbound from its driver.
1332  * If for some reason the resource needs to be released explicitly, because
1333  * of ordering issues for example, drivers must call devm_release_resource()
1334  * rather than the regular release_resource().
1335  *
1336  * When a conflict is detected between any existing resources and the newly
1337  * requested resource, an error message will be printed.
1338  *
1339  * Returns 0 on success or a negative error code on failure.
1340  */
1341 int devm_request_resource(struct device *dev, struct resource *root,
1342                           struct resource *new)
1343 {
1344         struct resource *conflict, **ptr;
1345 
1346         ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
1347         if (!ptr)
1348                 return -ENOMEM;
1349 
1350         *ptr = new;
1351 
1352         conflict = request_resource_conflict(root, new);
1353         if (conflict) {
1354                 dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
1355                         new, conflict->name, conflict);
1356                 devres_free(ptr);
1357                 return -EBUSY;
1358         }
1359 
1360         devres_add(dev, ptr);
1361         return 0;
1362 }
1363 EXPORT_SYMBOL(devm_request_resource);
1364 
1365 static int devm_resource_match(struct device *dev, void *res, void *data)
1366 {
1367         struct resource **ptr = res;
1368 
1369         return *ptr == data;
1370 }
1371 
1372 /**
1373  * devm_release_resource() - release a previously requested resource
1374  * @dev: device for which to release the resource
1375  * @new: descriptor of the resource to release
1376  *
1377  * Releases a resource previously requested using devm_request_resource().
1378  */
1379 void devm_release_resource(struct device *dev, struct resource *new)
1380 {
1381         WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
1382                                new));
1383 }
1384 EXPORT_SYMBOL(devm_release_resource);
1385 
1386 struct region_devres {
1387         struct resource *parent;
1388         resource_size_t start;
1389         resource_size_t n;
1390 };
1391 
1392 static void devm_region_release(struct device *dev, void *res)
1393 {
1394         struct region_devres *this = res;
1395 
1396         __release_region(this->parent, this->start, this->n);
1397 }
1398 
1399 static int devm_region_match(struct device *dev, void *res, void *match_data)
1400 {
1401         struct region_devres *this = res, *match = match_data;
1402 
1403         return this->parent == match->parent &&
1404                 this->start == match->start && this->n == match->n;
1405 }
1406 
1407 struct resource *
1408 __devm_request_region(struct device *dev, struct resource *parent,
1409                       resource_size_t start, resource_size_t n, const char *name)
1410 {
1411         struct region_devres *dr = NULL;
1412         struct resource *res;
1413 
1414         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1415                           GFP_KERNEL);
1416         if (!dr)
1417                 return NULL;
1418 
1419         dr->parent = parent;
1420         dr->start = start;
1421         dr->n = n;
1422 
1423         res = __request_region(parent, start, n, name, 0);
1424         if (res)
1425                 devres_add(dev, dr);
1426         else
1427                 devres_free(dr);
1428 
1429         return res;
1430 }
1431 EXPORT_SYMBOL(__devm_request_region);
1432 
1433 void __devm_release_region(struct device *dev, struct resource *parent,
1434                            resource_size_t start, resource_size_t n)
1435 {
1436         struct region_devres match_data = { parent, start, n };
1437 
1438         __release_region(parent, start, n);
1439         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1440                                &match_data));
1441 }
1442 EXPORT_SYMBOL(__devm_release_region);
1443 
1444 /*
1445  * Reserve I/O ports or memory based on "reserve=" kernel parameter.
1446  */
1447 #define MAXRESERVE 4
1448 static int __init reserve_setup(char *str)
1449 {
1450         static int reserved;
1451         static struct resource reserve[MAXRESERVE];
1452 
1453         for (;;) {
1454                 unsigned int io_start, io_num;
1455                 int x = reserved;
1456                 struct resource *parent;
1457 
1458                 if (get_option(&str, &io_start) != 2)
1459                         break;
1460                 if (get_option(&str, &io_num) == 0)
1461                         break;
1462                 if (x < MAXRESERVE) {
1463                         struct resource *res = reserve + x;
1464 
1465                         /*
1466                          * If the region starts below 0x10000, we assume it's
1467                          * I/O port space; otherwise assume it's memory.
1468                          */
1469                         if (io_start < 0x10000) {
1470                                 res->flags = IORESOURCE_IO;
1471                                 parent = &ioport_resource;
1472                         } else {
1473                                 res->flags = IORESOURCE_MEM;
1474                                 parent = &iomem_resource;
1475                         }
1476                         res->name = "reserved";
1477                         res->start = io_start;
1478                         res->end = io_start + io_num - 1;
1479                         res->flags |= IORESOURCE_BUSY;
1480                         res->desc = IORES_DESC_NONE;
1481                         res->child = NULL;
1482                         if (request_resource(parent, res) == 0)
1483                                 reserved = x+1;
1484                 }
1485         }
1486         return 1;
1487 }
1488 __setup("reserve=", reserve_setup);
1489 
1490 /*
1491  * Check if the requested addr and size spans more than any slot in the
1492  * iomem resource tree.
1493  */
1494 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1495 {
1496         struct resource *p = &iomem_resource;
1497         int err = 0;
1498         loff_t l;
1499 
1500         read_lock(&resource_lock);
1501         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1502                 /*
1503                  * We can probably skip the resources without
1504                  * IORESOURCE_IO attribute?
1505                  */
1506                 if (p->start >= addr + size)
1507                         continue;
1508                 if (p->end < addr)
1509                         continue;
1510                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1511                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1512                         continue;
1513                 /*
1514                  * if a resource is "BUSY", it's not a hardware resource
1515                  * but a driver mapping of such a resource; we don't want
1516                  * to warn for those; some drivers legitimately map only
1517                  * partial hardware resources. (example: vesafb)
1518                  */
1519                 if (p->flags & IORESOURCE_BUSY)
1520                         continue;
1521 
1522                 printk(KERN_WARNING "resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
1523                        (unsigned long long)addr,
1524                        (unsigned long long)(addr + size - 1),
1525                        p->name, p);
1526                 err = -1;
1527                 break;
1528         }
1529         read_unlock(&resource_lock);
1530 
1531         return err;
1532 }
1533 
1534 #ifdef CONFIG_STRICT_DEVMEM
1535 static int strict_iomem_checks = 1;
1536 #else
1537 static int strict_iomem_checks;
1538 #endif
1539 
1540 /*
1541  * check if an address is reserved in the iomem resource tree
1542  * returns true if reserved, false if not reserved.
1543  */
1544 bool iomem_is_exclusive(u64 addr)
1545 {
1546         struct resource *p = &iomem_resource;
1547         bool err = false;
1548         loff_t l;
1549         int size = PAGE_SIZE;
1550 
1551         if (!strict_iomem_checks)
1552                 return false;
1553 
1554         addr = addr & PAGE_MASK;
1555 
1556         read_lock(&resource_lock);
1557         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1558                 /*
1559                  * We can probably skip the resources without
1560                  * IORESOURCE_IO attribute?
1561                  */
1562                 if (p->start >= addr + size)
1563                         break;
1564                 if (p->end < addr)
1565                         continue;
1566                 /*
1567                  * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
1568                  * or CONFIG_IO_STRICT_DEVMEM is enabled and the
1569                  * resource is busy.
1570                  */
1571                 if ((p->flags & IORESOURCE_BUSY) == 0)
1572                         continue;
1573                 if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM)
1574                                 || p->flags & IORESOURCE_EXCLUSIVE) {
1575                         err = true;
1576                         break;
1577                 }
1578         }
1579         read_unlock(&resource_lock);
1580 
1581         return err;
1582 }
1583 
1584 struct resource_entry *resource_list_create_entry(struct resource *res,
1585                                                   size_t extra_size)
1586 {
1587         struct resource_entry *entry;
1588 
1589         entry = kzalloc(sizeof(*entry) + extra_size, GFP_KERNEL);
1590         if (entry) {
1591                 INIT_LIST_HEAD(&entry->node);
1592                 entry->res = res ? res : &entry->__res;
1593         }
1594 
1595         return entry;
1596 }
1597 EXPORT_SYMBOL(resource_list_create_entry);
1598 
1599 void resource_list_free(struct list_head *head)
1600 {
1601         struct resource_entry *entry, *tmp;
1602 
1603         list_for_each_entry_safe(entry, tmp, head, node)
1604                 resource_list_destroy_entry(entry);
1605 }
1606 EXPORT_SYMBOL(resource_list_free);
1607 
1608 static int __init strict_iomem(char *str)
1609 {
1610         if (strstr(str, "relaxed"))
1611                 strict_iomem_checks = 0;
1612         if (strstr(str, "strict"))
1613                 strict_iomem_checks = 1;
1614         return 1;
1615 }
1616 
1617 __setup("iomem=", strict_iomem);
1618 

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