1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/resource.c
5 * Copyright (C) 1999 Linus Torvalds
6 * Copyright (C) 1999 Martin Mares <mj@ucw.cz>
8 * Arbitrary resource management.
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/export.h>
14 #include <linux/errno.h>
15 #include <linux/ioport.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
20 #include <linux/proc_fs.h>
21 #include <linux/pseudo_fs.h>
22 #include <linux/sched.h>
23 #include <linux/seq_file.h>
24 #include <linux/device.h>
25 #include <linux/pfn.h>
27 #include <linux/mount.h>
28 #include <linux/resource_ext.h>
29 #include <uapi/linux/magic.h>
33 struct resource ioport_resource
= {
36 .end
= IO_SPACE_LIMIT
,
37 .flags
= IORESOURCE_IO
,
39 EXPORT_SYMBOL(ioport_resource
);
41 struct resource iomem_resource
= {
45 .flags
= IORESOURCE_MEM
,
47 EXPORT_SYMBOL(iomem_resource
);
49 /* constraints to be met while allocating resources */
50 struct resource_constraint
{
51 resource_size_t min
, max
, align
;
52 resource_size_t (*alignf
)(void *, const struct resource
*,
53 resource_size_t
, resource_size_t
);
57 static DEFINE_RWLOCK(resource_lock
);
60 * For memory hotplug, there is no way to free resource entries allocated
61 * by boot mem after the system is up. So for reusing the resource entry
62 * we need to remember the resource.
64 static struct resource
*bootmem_resource_free
;
65 static DEFINE_SPINLOCK(bootmem_resource_lock
);
67 static struct resource
*next_resource(struct resource
*p
, bool sibling_only
)
69 /* Caller wants to traverse through siblings only */
75 while (!p
->sibling
&& p
->parent
)
80 static void *r_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
82 struct resource
*p
= v
;
84 return (void *)next_resource(p
, false);
89 enum { MAX_IORES_LEVEL
= 5 };
91 static void *r_start(struct seq_file
*m
, loff_t
*pos
)
92 __acquires(resource_lock
)
94 struct resource
*p
= PDE_DATA(file_inode(m
->file
));
96 read_lock(&resource_lock
);
97 for (p
= p
->child
; p
&& l
< *pos
; p
= r_next(m
, p
, &l
))
102 static void r_stop(struct seq_file
*m
, void *v
)
103 __releases(resource_lock
)
105 read_unlock(&resource_lock
);
108 static int r_show(struct seq_file
*m
, void *v
)
110 struct resource
*root
= PDE_DATA(file_inode(m
->file
));
111 struct resource
*r
= v
, *p
;
112 unsigned long long start
, end
;
113 int width
= root
->end
< 0x10000 ? 4 : 8;
116 for (depth
= 0, p
= r
; depth
< MAX_IORES_LEVEL
; depth
++, p
= p
->parent
)
117 if (p
->parent
== root
)
120 if (file_ns_capable(m
->file
, &init_user_ns
, CAP_SYS_ADMIN
)) {
127 seq_printf(m
, "%*s%0*llx-%0*llx : %s\n",
131 r
->name
? r
->name
: "<BAD>");
135 static const struct seq_operations resource_op
= {
142 static int __init
ioresources_init(void)
144 proc_create_seq_data("ioports", 0, NULL
, &resource_op
,
146 proc_create_seq_data("iomem", 0, NULL
, &resource_op
, &iomem_resource
);
149 __initcall(ioresources_init
);
151 #endif /* CONFIG_PROC_FS */
153 static void free_resource(struct resource
*res
)
158 if (!PageSlab(virt_to_head_page(res
))) {
159 spin_lock(&bootmem_resource_lock
);
160 res
->sibling
= bootmem_resource_free
;
161 bootmem_resource_free
= res
;
162 spin_unlock(&bootmem_resource_lock
);
168 static struct resource
*alloc_resource(gfp_t flags
)
170 struct resource
*res
= NULL
;
172 spin_lock(&bootmem_resource_lock
);
173 if (bootmem_resource_free
) {
174 res
= bootmem_resource_free
;
175 bootmem_resource_free
= res
->sibling
;
177 spin_unlock(&bootmem_resource_lock
);
180 memset(res
, 0, sizeof(struct resource
));
182 res
= kzalloc(sizeof(struct resource
), flags
);
187 /* Return the conflict entry if you can't request it */
188 static struct resource
* __request_resource(struct resource
*root
, struct resource
*new)
190 resource_size_t start
= new->start
;
191 resource_size_t end
= new->end
;
192 struct resource
*tmp
, **p
;
196 if (start
< root
->start
)
203 if (!tmp
|| tmp
->start
> end
) {
210 if (tmp
->end
< start
)
216 static int __release_resource(struct resource
*old
, bool release_child
)
218 struct resource
*tmp
, **p
, *chd
;
220 p
= &old
->parent
->child
;
226 if (release_child
|| !(tmp
->child
)) {
229 for (chd
= tmp
->child
;; chd
= chd
->sibling
) {
230 chd
->parent
= tmp
->parent
;
235 chd
->sibling
= tmp
->sibling
;
245 static void __release_child_resources(struct resource
*r
)
247 struct resource
*tmp
, *p
;
248 resource_size_t size
;
258 __release_child_resources(tmp
);
260 printk(KERN_DEBUG
"release child resource %pR\n", tmp
);
261 /* need to restore size, and keep flags */
262 size
= resource_size(tmp
);
268 void release_child_resources(struct resource
*r
)
270 write_lock(&resource_lock
);
271 __release_child_resources(r
);
272 write_unlock(&resource_lock
);
276 * request_resource_conflict - request and reserve an I/O or memory resource
277 * @root: root resource descriptor
278 * @new: resource descriptor desired by caller
280 * Returns 0 for success, conflict resource on error.
282 struct resource
*request_resource_conflict(struct resource
*root
, struct resource
*new)
284 struct resource
*conflict
;
286 write_lock(&resource_lock
);
287 conflict
= __request_resource(root
, new);
288 write_unlock(&resource_lock
);
293 * request_resource - request and reserve an I/O or memory resource
294 * @root: root resource descriptor
295 * @new: resource descriptor desired by caller
297 * Returns 0 for success, negative error code on error.
299 int request_resource(struct resource
*root
, struct resource
*new)
301 struct resource
*conflict
;
303 conflict
= request_resource_conflict(root
, new);
304 return conflict
? -EBUSY
: 0;
307 EXPORT_SYMBOL(request_resource
);
310 * release_resource - release a previously reserved resource
311 * @old: resource pointer
313 int release_resource(struct resource
*old
)
317 write_lock(&resource_lock
);
318 retval
= __release_resource(old
, true);
319 write_unlock(&resource_lock
);
323 EXPORT_SYMBOL(release_resource
);
326 * find_next_iomem_res - Finds the lowest iomem resource that covers part of
329 * If a resource is found, returns 0 and @*res is overwritten with the part
330 * of the resource that's within [@start..@end]; if none is found, returns
331 * -ENODEV. Returns -EINVAL for invalid parameters.
333 * This function walks the whole tree and not just first level children
334 * unless @first_lvl is true.
336 * @start: start address of the resource searched for
337 * @end: end address of same resource
338 * @flags: flags which the resource must have
339 * @desc: descriptor the resource must have
340 * @first_lvl: walk only the first level children, if set
341 * @res: return ptr, if resource found
343 * The caller must specify @start, @end, @flags, and @desc
344 * (which may be IORES_DESC_NONE).
346 static int find_next_iomem_res(resource_size_t start
, resource_size_t end
,
347 unsigned long flags
, unsigned long desc
,
348 bool first_lvl
, struct resource
*res
)
350 bool siblings_only
= true;
359 read_lock(&resource_lock
);
361 for (p
= iomem_resource
.child
; p
; p
= next_resource(p
, siblings_only
)) {
362 /* If we passed the resource we are looking for, stop */
363 if (p
->start
> end
) {
368 /* Skip until we find a range that matches what we look for */
373 * Now that we found a range that matches what we look for,
374 * check the flags and the descriptor. If we were not asked to
375 * use only the first level, start looking at children as well.
377 siblings_only
= first_lvl
;
379 if ((p
->flags
& flags
) != flags
)
381 if ((desc
!= IORES_DESC_NONE
) && (desc
!= p
->desc
))
384 /* Found a match, break */
390 *res
= (struct resource
) {
391 .start
= max(start
, p
->start
),
392 .end
= min(end
, p
->end
),
399 read_unlock(&resource_lock
);
400 return p
? 0 : -ENODEV
;
403 static int __walk_iomem_res_desc(resource_size_t start
, resource_size_t end
,
404 unsigned long flags
, unsigned long desc
,
405 bool first_lvl
, void *arg
,
406 int (*func
)(struct resource
*, void *))
411 while (start
< end
&&
412 !find_next_iomem_res(start
, end
, flags
, desc
, first_lvl
, &res
)) {
413 ret
= (*func
)(&res
, arg
);
424 * walk_iomem_res_desc - Walks through iomem resources and calls func()
425 * with matching resource ranges.
427 * @desc: I/O resource descriptor. Use IORES_DESC_NONE to skip @desc check.
428 * @flags: I/O resource flags
431 * @arg: function argument for the callback @func
432 * @func: callback function that is called for each qualifying resource area
434 * This walks through whole tree and not just first level children.
435 * All the memory ranges which overlap start,end and also match flags and
436 * desc are valid candidates.
438 * NOTE: For a new descriptor search, define a new IORES_DESC in
439 * <linux/ioport.h> and set it in 'desc' of a target resource entry.
441 int walk_iomem_res_desc(unsigned long desc
, unsigned long flags
, u64 start
,
442 u64 end
, void *arg
, int (*func
)(struct resource
*, void *))
444 return __walk_iomem_res_desc(start
, end
, flags
, desc
, false, arg
, func
);
446 EXPORT_SYMBOL_GPL(walk_iomem_res_desc
);
449 * This function calls the @func callback against all memory ranges of type
450 * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
451 * Now, this function is only for System RAM, it deals with full ranges and
452 * not PFNs. If resources are not PFN-aligned, dealing with PFNs can truncate
455 int walk_system_ram_res(u64 start
, u64 end
, void *arg
,
456 int (*func
)(struct resource
*, void *))
458 unsigned long flags
= IORESOURCE_SYSTEM_RAM
| IORESOURCE_BUSY
;
460 return __walk_iomem_res_desc(start
, end
, flags
, IORES_DESC_NONE
, true,
465 * This function calls the @func callback against all memory ranges, which
466 * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
468 int walk_mem_res(u64 start
, u64 end
, void *arg
,
469 int (*func
)(struct resource
*, void *))
471 unsigned long flags
= IORESOURCE_MEM
| IORESOURCE_BUSY
;
473 return __walk_iomem_res_desc(start
, end
, flags
, IORES_DESC_NONE
, true,
478 * This function calls the @func callback against all memory ranges of type
479 * System RAM which are marked as IORESOURCE_SYSTEM_RAM and IORESOUCE_BUSY.
480 * It is to be used only for System RAM.
482 * This will find System RAM ranges that are children of top-level resources
483 * in addition to top-level System RAM resources.
485 int walk_system_ram_range(unsigned long start_pfn
, unsigned long nr_pages
,
486 void *arg
, int (*func
)(unsigned long, unsigned long, void *))
488 resource_size_t start
, end
;
491 unsigned long pfn
, end_pfn
;
494 start
= (u64
) start_pfn
<< PAGE_SHIFT
;
495 end
= ((u64
)(start_pfn
+ nr_pages
) << PAGE_SHIFT
) - 1;
496 flags
= IORESOURCE_SYSTEM_RAM
| IORESOURCE_BUSY
;
497 while (start
< end
&&
498 !find_next_iomem_res(start
, end
, flags
, IORES_DESC_NONE
,
500 pfn
= PFN_UP(res
.start
);
501 end_pfn
= PFN_DOWN(res
.end
+ 1);
503 ret
= (*func
)(pfn
, end_pfn
- pfn
, arg
);
511 static int __is_ram(unsigned long pfn
, unsigned long nr_pages
, void *arg
)
517 * This generic page_is_ram() returns true if specified address is
518 * registered as System RAM in iomem_resource list.
520 int __weak
page_is_ram(unsigned long pfn
)
522 return walk_system_ram_range(pfn
, 1, NULL
, __is_ram
) == 1;
524 EXPORT_SYMBOL_GPL(page_is_ram
);
527 * region_intersects() - determine intersection of region with known resources
528 * @start: region start address
529 * @size: size of region
530 * @flags: flags of resource (in iomem_resource)
531 * @desc: descriptor of resource (in iomem_resource) or IORES_DESC_NONE
533 * Check if the specified region partially overlaps or fully eclipses a
534 * resource identified by @flags and @desc (optional with IORES_DESC_NONE).
535 * Return REGION_DISJOINT if the region does not overlap @flags/@desc,
536 * return REGION_MIXED if the region overlaps @flags/@desc and another
537 * resource, and return REGION_INTERSECTS if the region overlaps @flags/@desc
538 * and no other defined resource. Note that REGION_INTERSECTS is also
539 * returned in the case when the specified region overlaps RAM and undefined
542 * region_intersect() is used by memory remapping functions to ensure
543 * the user is not remapping RAM and is a vast speed up over walking
544 * through the resource table page by page.
546 int region_intersects(resource_size_t start
, size_t size
, unsigned long flags
,
550 int type
= 0; int other
= 0;
554 res
.end
= start
+ size
- 1;
556 read_lock(&resource_lock
);
557 for (p
= iomem_resource
.child
; p
; p
= p
->sibling
) {
558 bool is_type
= (((p
->flags
& flags
) == flags
) &&
559 ((desc
== IORES_DESC_NONE
) ||
562 if (resource_overlaps(p
, &res
))
563 is_type
? type
++ : other
++;
565 read_unlock(&resource_lock
);
568 return REGION_DISJOINT
;
571 return REGION_INTERSECTS
;
575 EXPORT_SYMBOL_GPL(region_intersects
);
577 void __weak
arch_remove_reservations(struct resource
*avail
)
581 static resource_size_t
simple_align_resource(void *data
,
582 const struct resource
*avail
,
583 resource_size_t size
,
584 resource_size_t align
)
589 static void resource_clip(struct resource
*res
, resource_size_t min
,
592 if (res
->start
< min
)
599 * Find empty slot in the resource tree with the given range and
600 * alignment constraints
602 static int __find_resource(struct resource
*root
, struct resource
*old
,
603 struct resource
*new,
604 resource_size_t size
,
605 struct resource_constraint
*constraint
)
607 struct resource
*this = root
->child
;
608 struct resource tmp
= *new, avail
, alloc
;
610 tmp
.start
= root
->start
;
612 * Skip past an allocated resource that starts at 0, since the assignment
613 * of this->start - 1 to tmp->end below would cause an underflow.
615 if (this && this->start
== root
->start
) {
616 tmp
.start
= (this == old
) ? old
->start
: this->end
+ 1;
617 this = this->sibling
;
621 tmp
.end
= (this == old
) ? this->end
: this->start
- 1;
625 if (tmp
.end
< tmp
.start
)
628 resource_clip(&tmp
, constraint
->min
, constraint
->max
);
629 arch_remove_reservations(&tmp
);
631 /* Check for overflow after ALIGN() */
632 avail
.start
= ALIGN(tmp
.start
, constraint
->align
);
634 avail
.flags
= new->flags
& ~IORESOURCE_UNSET
;
635 if (avail
.start
>= tmp
.start
) {
636 alloc
.flags
= avail
.flags
;
637 alloc
.start
= constraint
->alignf(constraint
->alignf_data
, &avail
,
638 size
, constraint
->align
);
639 alloc
.end
= alloc
.start
+ size
- 1;
640 if (alloc
.start
<= alloc
.end
&&
641 resource_contains(&avail
, &alloc
)) {
642 new->start
= alloc
.start
;
643 new->end
= alloc
.end
;
648 next
: if (!this || this->end
== root
->end
)
652 tmp
.start
= this->end
+ 1;
653 this = this->sibling
;
659 * Find empty slot in the resource tree given range and alignment.
661 static int find_resource(struct resource
*root
, struct resource
*new,
662 resource_size_t size
,
663 struct resource_constraint
*constraint
)
665 return __find_resource(root
, NULL
, new, size
, constraint
);
669 * reallocate_resource - allocate a slot in the resource tree given range & alignment.
670 * The resource will be relocated if the new size cannot be reallocated in the
673 * @root: root resource descriptor
674 * @old: resource descriptor desired by caller
675 * @newsize: new size of the resource descriptor
676 * @constraint: the size and alignment constraints to be met.
678 static int reallocate_resource(struct resource
*root
, struct resource
*old
,
679 resource_size_t newsize
,
680 struct resource_constraint
*constraint
)
683 struct resource
new = *old
;
684 struct resource
*conflict
;
686 write_lock(&resource_lock
);
688 if ((err
= __find_resource(root
, old
, &new, newsize
, constraint
)))
691 if (resource_contains(&new, old
)) {
692 old
->start
= new.start
;
702 if (resource_contains(old
, &new)) {
703 old
->start
= new.start
;
706 __release_resource(old
, true);
708 conflict
= __request_resource(root
, old
);
712 write_unlock(&resource_lock
);
718 * allocate_resource - allocate empty slot in the resource tree given range & alignment.
719 * The resource will be reallocated with a new size if it was already allocated
720 * @root: root resource descriptor
721 * @new: resource descriptor desired by caller
722 * @size: requested resource region size
723 * @min: minimum boundary to allocate
724 * @max: maximum boundary to allocate
725 * @align: alignment requested, in bytes
726 * @alignf: alignment function, optional, called if not NULL
727 * @alignf_data: arbitrary data to pass to the @alignf function
729 int allocate_resource(struct resource
*root
, struct resource
*new,
730 resource_size_t size
, resource_size_t min
,
731 resource_size_t max
, resource_size_t align
,
732 resource_size_t (*alignf
)(void *,
733 const struct resource
*,
739 struct resource_constraint constraint
;
742 alignf
= simple_align_resource
;
744 constraint
.min
= min
;
745 constraint
.max
= max
;
746 constraint
.align
= align
;
747 constraint
.alignf
= alignf
;
748 constraint
.alignf_data
= alignf_data
;
751 /* resource is already allocated, try reallocating with
752 the new constraints */
753 return reallocate_resource(root
, new, size
, &constraint
);
756 write_lock(&resource_lock
);
757 err
= find_resource(root
, new, size
, &constraint
);
758 if (err
>= 0 && __request_resource(root
, new))
760 write_unlock(&resource_lock
);
764 EXPORT_SYMBOL(allocate_resource
);
767 * lookup_resource - find an existing resource by a resource start address
768 * @root: root resource descriptor
769 * @start: resource start address
771 * Returns a pointer to the resource if found, NULL otherwise
773 struct resource
*lookup_resource(struct resource
*root
, resource_size_t start
)
775 struct resource
*res
;
777 read_lock(&resource_lock
);
778 for (res
= root
->child
; res
; res
= res
->sibling
) {
779 if (res
->start
== start
)
782 read_unlock(&resource_lock
);
788 * Insert a resource into the resource tree. If successful, return NULL,
789 * otherwise return the conflicting resource (compare to __request_resource())
791 static struct resource
* __insert_resource(struct resource
*parent
, struct resource
*new)
793 struct resource
*first
, *next
;
795 for (;; parent
= first
) {
796 first
= __request_resource(parent
, new);
802 if (WARN_ON(first
== new)) /* duplicated insertion */
805 if ((first
->start
> new->start
) || (first
->end
< new->end
))
807 if ((first
->start
== new->start
) && (first
->end
== new->end
))
811 for (next
= first
; ; next
= next
->sibling
) {
812 /* Partial overlap? Bad, and unfixable */
813 if (next
->start
< new->start
|| next
->end
> new->end
)
817 if (next
->sibling
->start
> new->end
)
821 new->parent
= parent
;
822 new->sibling
= next
->sibling
;
825 next
->sibling
= NULL
;
826 for (next
= first
; next
; next
= next
->sibling
)
829 if (parent
->child
== first
) {
832 next
= parent
->child
;
833 while (next
->sibling
!= first
)
834 next
= next
->sibling
;
841 * insert_resource_conflict - Inserts resource in the resource tree
842 * @parent: parent of the new resource
843 * @new: new resource to insert
845 * Returns 0 on success, conflict resource if the resource can't be inserted.
847 * This function is equivalent to request_resource_conflict when no conflict
848 * happens. If a conflict happens, and the conflicting resources
849 * entirely fit within the range of the new resource, then the new
850 * resource is inserted and the conflicting resources become children of
853 * This function is intended for producers of resources, such as FW modules
856 struct resource
*insert_resource_conflict(struct resource
*parent
, struct resource
*new)
858 struct resource
*conflict
;
860 write_lock(&resource_lock
);
861 conflict
= __insert_resource(parent
, new);
862 write_unlock(&resource_lock
);
867 * insert_resource - Inserts a resource in the resource tree
868 * @parent: parent of the new resource
869 * @new: new resource to insert
871 * Returns 0 on success, -EBUSY if the resource can't be inserted.
873 * This function is intended for producers of resources, such as FW modules
876 int insert_resource(struct resource
*parent
, struct resource
*new)
878 struct resource
*conflict
;
880 conflict
= insert_resource_conflict(parent
, new);
881 return conflict
? -EBUSY
: 0;
883 EXPORT_SYMBOL_GPL(insert_resource
);
886 * insert_resource_expand_to_fit - Insert a resource into the resource tree
887 * @root: root resource descriptor
888 * @new: new resource to insert
890 * Insert a resource into the resource tree, possibly expanding it in order
891 * to make it encompass any conflicting resources.
893 void insert_resource_expand_to_fit(struct resource
*root
, struct resource
*new)
898 write_lock(&resource_lock
);
900 struct resource
*conflict
;
902 conflict
= __insert_resource(root
, new);
905 if (conflict
== root
)
908 /* Ok, expand resource to cover the conflict, then try again .. */
909 if (conflict
->start
< new->start
)
910 new->start
= conflict
->start
;
911 if (conflict
->end
> new->end
)
912 new->end
= conflict
->end
;
914 printk("Expanded resource %s due to conflict with %s\n", new->name
, conflict
->name
);
916 write_unlock(&resource_lock
);
920 * remove_resource - Remove a resource in the resource tree
921 * @old: resource to remove
923 * Returns 0 on success, -EINVAL if the resource is not valid.
925 * This function removes a resource previously inserted by insert_resource()
926 * or insert_resource_conflict(), and moves the children (if any) up to
927 * where they were before. insert_resource() and insert_resource_conflict()
928 * insert a new resource, and move any conflicting resources down to the
929 * children of the new resource.
931 * insert_resource(), insert_resource_conflict() and remove_resource() are
932 * intended for producers of resources, such as FW modules and bus drivers.
934 int remove_resource(struct resource
*old
)
938 write_lock(&resource_lock
);
939 retval
= __release_resource(old
, false);
940 write_unlock(&resource_lock
);
943 EXPORT_SYMBOL_GPL(remove_resource
);
945 static int __adjust_resource(struct resource
*res
, resource_size_t start
,
946 resource_size_t size
)
948 struct resource
*tmp
, *parent
= res
->parent
;
949 resource_size_t end
= start
+ size
- 1;
955 if ((start
< parent
->start
) || (end
> parent
->end
))
958 if (res
->sibling
&& (res
->sibling
->start
<= end
))
963 while (tmp
->sibling
!= res
)
965 if (start
<= tmp
->end
)
970 for (tmp
= res
->child
; tmp
; tmp
= tmp
->sibling
)
971 if ((tmp
->start
< start
) || (tmp
->end
> end
))
983 * adjust_resource - modify a resource's start and size
984 * @res: resource to modify
985 * @start: new start value
988 * Given an existing resource, change its start and size to match the
989 * arguments. Returns 0 on success, -EBUSY if it can't fit.
990 * Existing children of the resource are assumed to be immutable.
992 int adjust_resource(struct resource
*res
, resource_size_t start
,
993 resource_size_t size
)
997 write_lock(&resource_lock
);
998 result
= __adjust_resource(res
, start
, size
);
999 write_unlock(&resource_lock
);
1002 EXPORT_SYMBOL(adjust_resource
);
1005 __reserve_region_with_split(struct resource
*root
, resource_size_t start
,
1006 resource_size_t end
, const char *name
)
1008 struct resource
*parent
= root
;
1009 struct resource
*conflict
;
1010 struct resource
*res
= alloc_resource(GFP_ATOMIC
);
1011 struct resource
*next_res
= NULL
;
1012 int type
= resource_type(root
);
1020 res
->flags
= type
| IORESOURCE_BUSY
;
1021 res
->desc
= IORES_DESC_NONE
;
1025 conflict
= __request_resource(parent
, res
);
1034 /* conflict covered whole area */
1035 if (conflict
->start
<= res
->start
&&
1036 conflict
->end
>= res
->end
) {
1042 /* failed, split and try again */
1043 if (conflict
->start
> res
->start
) {
1045 res
->end
= conflict
->start
- 1;
1046 if (conflict
->end
< end
) {
1047 next_res
= alloc_resource(GFP_ATOMIC
);
1052 next_res
->name
= name
;
1053 next_res
->start
= conflict
->end
+ 1;
1054 next_res
->end
= end
;
1055 next_res
->flags
= type
| IORESOURCE_BUSY
;
1056 next_res
->desc
= IORES_DESC_NONE
;
1059 res
->start
= conflict
->end
+ 1;
1066 reserve_region_with_split(struct resource
*root
, resource_size_t start
,
1067 resource_size_t end
, const char *name
)
1071 write_lock(&resource_lock
);
1072 if (root
->start
> start
|| root
->end
< end
) {
1073 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
1074 (unsigned long long)start
, (unsigned long long)end
,
1076 if (start
> root
->end
|| end
< root
->start
)
1079 if (end
> root
->end
)
1081 if (start
< root
->start
)
1082 start
= root
->start
;
1083 pr_err("fixing request to [0x%llx-0x%llx]\n",
1084 (unsigned long long)start
,
1085 (unsigned long long)end
);
1090 __reserve_region_with_split(root
, start
, end
, name
);
1091 write_unlock(&resource_lock
);
1095 * resource_alignment - calculate resource's alignment
1096 * @res: resource pointer
1098 * Returns alignment on success, 0 (invalid alignment) on failure.
1100 resource_size_t
resource_alignment(struct resource
*res
)
1102 switch (res
->flags
& (IORESOURCE_SIZEALIGN
| IORESOURCE_STARTALIGN
)) {
1103 case IORESOURCE_SIZEALIGN
:
1104 return resource_size(res
);
1105 case IORESOURCE_STARTALIGN
:
1113 * This is compatibility stuff for IO resources.
1115 * Note how this, unlike the above, knows about
1116 * the IO flag meanings (busy etc).
1118 * request_region creates a new busy region.
1120 * release_region releases a matching busy region.
1123 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait
);
1125 static struct inode
*iomem_inode
;
1127 #ifdef CONFIG_IO_STRICT_DEVMEM
1128 static void revoke_iomem(struct resource
*res
)
1130 /* pairs with smp_store_release() in iomem_init_inode() */
1131 struct inode
*inode
= smp_load_acquire(&iomem_inode
);
1134 * Check that the initialization has completed. Losing the race
1135 * is ok because it means drivers are claiming resources before
1136 * the fs_initcall level of init and prevent iomem_get_mapping users
1137 * from establishing mappings.
1143 * The expectation is that the driver has successfully marked
1144 * the resource busy by this point, so devmem_is_allowed()
1145 * should start returning false, however for performance this
1146 * does not iterate the entire resource range.
1148 if (devmem_is_allowed(PHYS_PFN(res
->start
)) &&
1149 devmem_is_allowed(PHYS_PFN(res
->end
))) {
1151 * *cringe* iomem=relaxed says "go ahead, what's the
1152 * worst that can happen?"
1157 unmap_mapping_range(inode
->i_mapping
, res
->start
, resource_size(res
), 1);
1160 static void revoke_iomem(struct resource
*res
) {}
1163 struct address_space
*iomem_get_mapping(void)
1166 * This function is only called from file open paths, hence guaranteed
1167 * that fs_initcalls have completed and no need to check for NULL. But
1168 * since revoke_iomem can be called before the initcall we still need
1169 * the barrier to appease checkers.
1171 return smp_load_acquire(&iomem_inode
)->i_mapping
;
1175 * __request_region - create a new busy resource region
1176 * @parent: parent resource descriptor
1177 * @start: resource start address
1178 * @n: resource region size
1179 * @name: reserving caller's ID string
1180 * @flags: IO resource flags
1182 struct resource
* __request_region(struct resource
*parent
,
1183 resource_size_t start
, resource_size_t n
,
1184 const char *name
, int flags
)
1186 DECLARE_WAITQUEUE(wait
, current
);
1187 struct resource
*res
= alloc_resource(GFP_KERNEL
);
1188 struct resource
*orig_parent
= parent
;
1195 res
->end
= start
+ n
- 1;
1197 write_lock(&resource_lock
);
1200 struct resource
*conflict
;
1202 res
->flags
= resource_type(parent
) | resource_ext_type(parent
);
1203 res
->flags
|= IORESOURCE_BUSY
| flags
;
1204 res
->desc
= parent
->desc
;
1206 conflict
= __request_resource(parent
, res
);
1210 * mm/hmm.c reserves physical addresses which then
1211 * become unavailable to other users. Conflicts are
1212 * not expected. Warn to aid debugging if encountered.
1214 if (conflict
->desc
== IORES_DESC_DEVICE_PRIVATE_MEMORY
) {
1215 pr_warn("Unaddressable device %s %pR conflicts with %pR",
1216 conflict
->name
, conflict
, res
);
1218 if (conflict
!= parent
) {
1219 if (!(conflict
->flags
& IORESOURCE_BUSY
)) {
1224 if (conflict
->flags
& flags
& IORESOURCE_MUXED
) {
1225 add_wait_queue(&muxed_resource_wait
, &wait
);
1226 write_unlock(&resource_lock
);
1227 set_current_state(TASK_UNINTERRUPTIBLE
);
1229 remove_wait_queue(&muxed_resource_wait
, &wait
);
1230 write_lock(&resource_lock
);
1233 /* Uhhuh, that didn't work out.. */
1238 write_unlock(&resource_lock
);
1240 if (res
&& orig_parent
== &iomem_resource
)
1245 EXPORT_SYMBOL(__request_region
);
1248 * __release_region - release a previously reserved resource region
1249 * @parent: parent resource descriptor
1250 * @start: resource start address
1251 * @n: resource region size
1253 * The described resource region must match a currently busy region.
1255 void __release_region(struct resource
*parent
, resource_size_t start
,
1258 struct resource
**p
;
1259 resource_size_t end
;
1262 end
= start
+ n
- 1;
1264 write_lock(&resource_lock
);
1267 struct resource
*res
= *p
;
1271 if (res
->start
<= start
&& res
->end
>= end
) {
1272 if (!(res
->flags
& IORESOURCE_BUSY
)) {
1276 if (res
->start
!= start
|| res
->end
!= end
)
1279 write_unlock(&resource_lock
);
1280 if (res
->flags
& IORESOURCE_MUXED
)
1281 wake_up(&muxed_resource_wait
);
1288 write_unlock(&resource_lock
);
1290 printk(KERN_WARNING
"Trying to free nonexistent resource "
1291 "<%016llx-%016llx>\n", (unsigned long long)start
,
1292 (unsigned long long)end
);
1294 EXPORT_SYMBOL(__release_region
);
1296 #ifdef CONFIG_MEMORY_HOTREMOVE
1298 * release_mem_region_adjustable - release a previously reserved memory region
1299 * @start: resource start address
1300 * @size: resource region size
1302 * This interface is intended for memory hot-delete. The requested region
1303 * is released from a currently busy memory resource. The requested region
1304 * must either match exactly or fit into a single busy resource entry. In
1305 * the latter case, the remaining resource is adjusted accordingly.
1306 * Existing children of the busy memory resource must be immutable in the
1310 * - Additional release conditions, such as overlapping region, can be
1311 * supported after they are confirmed as valid cases.
1312 * - When a busy memory resource gets split into two entries, the code
1313 * assumes that all children remain in the lower address entry for
1314 * simplicity. Enhance this logic when necessary.
1316 void release_mem_region_adjustable(resource_size_t start
, resource_size_t size
)
1318 struct resource
*parent
= &iomem_resource
;
1319 struct resource
*new_res
= NULL
;
1320 bool alloc_nofail
= false;
1321 struct resource
**p
;
1322 struct resource
*res
;
1323 resource_size_t end
;
1325 end
= start
+ size
- 1;
1326 if (WARN_ON_ONCE((start
< parent
->start
) || (end
> parent
->end
)))
1330 * We free up quite a lot of memory on memory hotunplug (esp., memap),
1331 * just before releasing the region. This is highly unlikely to
1332 * fail - let's play save and make it never fail as the caller cannot
1333 * perform any error handling (e.g., trying to re-add memory will fail
1337 new_res
= alloc_resource(GFP_KERNEL
| (alloc_nofail
? __GFP_NOFAIL
: 0));
1340 write_lock(&resource_lock
);
1342 while ((res
= *p
)) {
1343 if (res
->start
>= end
)
1346 /* look for the next resource if it does not fit into */
1347 if (res
->start
> start
|| res
->end
< end
) {
1353 * All memory regions added from memory-hotplug path have the
1354 * flag IORESOURCE_SYSTEM_RAM. If the resource does not have
1355 * this flag, we know that we are dealing with a resource coming
1356 * from HMM/devm. HMM/devm use another mechanism to add/release
1357 * a resource. This goes via devm_request_mem_region and
1358 * devm_release_mem_region.
1359 * HMM/devm take care to release their resources when they want,
1360 * so if we are dealing with them, let us just back off here.
1362 if (!(res
->flags
& IORESOURCE_SYSRAM
)) {
1366 if (!(res
->flags
& IORESOURCE_MEM
))
1369 if (!(res
->flags
& IORESOURCE_BUSY
)) {
1374 /* found the target resource; let's adjust accordingly */
1375 if (res
->start
== start
&& res
->end
== end
) {
1376 /* free the whole entry */
1379 } else if (res
->start
== start
&& res
->end
!= end
) {
1380 /* adjust the start */
1381 WARN_ON_ONCE(__adjust_resource(res
, end
+ 1,
1383 } else if (res
->start
!= start
&& res
->end
== end
) {
1384 /* adjust the end */
1385 WARN_ON_ONCE(__adjust_resource(res
, res
->start
,
1386 start
- res
->start
));
1388 /* split into two entries - we need a new resource */
1390 new_res
= alloc_resource(GFP_ATOMIC
);
1392 alloc_nofail
= true;
1393 write_unlock(&resource_lock
);
1397 new_res
->name
= res
->name
;
1398 new_res
->start
= end
+ 1;
1399 new_res
->end
= res
->end
;
1400 new_res
->flags
= res
->flags
;
1401 new_res
->desc
= res
->desc
;
1402 new_res
->parent
= res
->parent
;
1403 new_res
->sibling
= res
->sibling
;
1404 new_res
->child
= NULL
;
1406 if (WARN_ON_ONCE(__adjust_resource(res
, res
->start
,
1407 start
- res
->start
)))
1409 res
->sibling
= new_res
;
1416 write_unlock(&resource_lock
);
1417 free_resource(new_res
);
1419 #endif /* CONFIG_MEMORY_HOTREMOVE */
1421 #ifdef CONFIG_MEMORY_HOTPLUG
1422 static bool system_ram_resources_mergeable(struct resource
*r1
,
1423 struct resource
*r2
)
1425 /* We assume either r1 or r2 is IORESOURCE_SYSRAM_MERGEABLE. */
1426 return r1
->flags
== r2
->flags
&& r1
->end
+ 1 == r2
->start
&&
1427 r1
->name
== r2
->name
&& r1
->desc
== r2
->desc
&&
1428 !r1
->child
&& !r2
->child
;
1432 * merge_system_ram_resource - mark the System RAM resource mergeable and try to
1433 * merge it with adjacent, mergeable resources
1434 * @res: resource descriptor
1436 * This interface is intended for memory hotplug, whereby lots of contiguous
1437 * system ram resources are added (e.g., via add_memory*()) by a driver, and
1438 * the actual resource boundaries are not of interest (e.g., it might be
1439 * relevant for DIMMs). Only resources that are marked mergeable, that have the
1440 * same parent, and that don't have any children are considered. All mergeable
1441 * resources must be immutable during the request.
1444 * - The caller has to make sure that no pointers to resources that are
1445 * marked mergeable are used anymore after this call - the resource might
1446 * be freed and the pointer might be stale!
1447 * - release_mem_region_adjustable() will split on demand on memory hotunplug
1449 void merge_system_ram_resource(struct resource
*res
)
1451 const unsigned long flags
= IORESOURCE_SYSTEM_RAM
| IORESOURCE_BUSY
;
1452 struct resource
*cur
;
1454 if (WARN_ON_ONCE((res
->flags
& flags
) != flags
))
1457 write_lock(&resource_lock
);
1458 res
->flags
|= IORESOURCE_SYSRAM_MERGEABLE
;
1460 /* Try to merge with next item in the list. */
1462 if (cur
&& system_ram_resources_mergeable(res
, cur
)) {
1463 res
->end
= cur
->end
;
1464 res
->sibling
= cur
->sibling
;
1468 /* Try to merge with previous item in the list. */
1469 cur
= res
->parent
->child
;
1470 while (cur
&& cur
->sibling
!= res
)
1472 if (cur
&& system_ram_resources_mergeable(cur
, res
)) {
1473 cur
->end
= res
->end
;
1474 cur
->sibling
= res
->sibling
;
1477 write_unlock(&resource_lock
);
1479 #endif /* CONFIG_MEMORY_HOTPLUG */
1482 * Managed region resource
1484 static void devm_resource_release(struct device
*dev
, void *ptr
)
1486 struct resource
**r
= ptr
;
1488 release_resource(*r
);
1492 * devm_request_resource() - request and reserve an I/O or memory resource
1493 * @dev: device for which to request the resource
1494 * @root: root of the resource tree from which to request the resource
1495 * @new: descriptor of the resource to request
1497 * This is a device-managed version of request_resource(). There is usually
1498 * no need to release resources requested by this function explicitly since
1499 * that will be taken care of when the device is unbound from its driver.
1500 * If for some reason the resource needs to be released explicitly, because
1501 * of ordering issues for example, drivers must call devm_release_resource()
1502 * rather than the regular release_resource().
1504 * When a conflict is detected between any existing resources and the newly
1505 * requested resource, an error message will be printed.
1507 * Returns 0 on success or a negative error code on failure.
1509 int devm_request_resource(struct device
*dev
, struct resource
*root
,
1510 struct resource
*new)
1512 struct resource
*conflict
, **ptr
;
1514 ptr
= devres_alloc(devm_resource_release
, sizeof(*ptr
), GFP_KERNEL
);
1520 conflict
= request_resource_conflict(root
, new);
1522 dev_err(dev
, "resource collision: %pR conflicts with %s %pR\n",
1523 new, conflict
->name
, conflict
);
1528 devres_add(dev
, ptr
);
1531 EXPORT_SYMBOL(devm_request_resource
);
1533 static int devm_resource_match(struct device
*dev
, void *res
, void *data
)
1535 struct resource
**ptr
= res
;
1537 return *ptr
== data
;
1541 * devm_release_resource() - release a previously requested resource
1542 * @dev: device for which to release the resource
1543 * @new: descriptor of the resource to release
1545 * Releases a resource previously requested using devm_request_resource().
1547 void devm_release_resource(struct device
*dev
, struct resource
*new)
1549 WARN_ON(devres_release(dev
, devm_resource_release
, devm_resource_match
,
1552 EXPORT_SYMBOL(devm_release_resource
);
1554 struct region_devres
{
1555 struct resource
*parent
;
1556 resource_size_t start
;
1560 static void devm_region_release(struct device
*dev
, void *res
)
1562 struct region_devres
*this = res
;
1564 __release_region(this->parent
, this->start
, this->n
);
1567 static int devm_region_match(struct device
*dev
, void *res
, void *match_data
)
1569 struct region_devres
*this = res
, *match
= match_data
;
1571 return this->parent
== match
->parent
&&
1572 this->start
== match
->start
&& this->n
== match
->n
;
1576 __devm_request_region(struct device
*dev
, struct resource
*parent
,
1577 resource_size_t start
, resource_size_t n
, const char *name
)
1579 struct region_devres
*dr
= NULL
;
1580 struct resource
*res
;
1582 dr
= devres_alloc(devm_region_release
, sizeof(struct region_devres
),
1587 dr
->parent
= parent
;
1591 res
= __request_region(parent
, start
, n
, name
, 0);
1593 devres_add(dev
, dr
);
1599 EXPORT_SYMBOL(__devm_request_region
);
1601 void __devm_release_region(struct device
*dev
, struct resource
*parent
,
1602 resource_size_t start
, resource_size_t n
)
1604 struct region_devres match_data
= { parent
, start
, n
};
1606 __release_region(parent
, start
, n
);
1607 WARN_ON(devres_destroy(dev
, devm_region_release
, devm_region_match
,
1610 EXPORT_SYMBOL(__devm_release_region
);
1613 * Reserve I/O ports or memory based on "reserve=" kernel parameter.
1615 #define MAXRESERVE 4
1616 static int __init
reserve_setup(char *str
)
1618 static int reserved
;
1619 static struct resource reserve
[MAXRESERVE
];
1622 unsigned int io_start
, io_num
;
1624 struct resource
*parent
;
1626 if (get_option(&str
, &io_start
) != 2)
1628 if (get_option(&str
, &io_num
) == 0)
1630 if (x
< MAXRESERVE
) {
1631 struct resource
*res
= reserve
+ x
;
1634 * If the region starts below 0x10000, we assume it's
1635 * I/O port space; otherwise assume it's memory.
1637 if (io_start
< 0x10000) {
1638 res
->flags
= IORESOURCE_IO
;
1639 parent
= &ioport_resource
;
1641 res
->flags
= IORESOURCE_MEM
;
1642 parent
= &iomem_resource
;
1644 res
->name
= "reserved";
1645 res
->start
= io_start
;
1646 res
->end
= io_start
+ io_num
- 1;
1647 res
->flags
|= IORESOURCE_BUSY
;
1648 res
->desc
= IORES_DESC_NONE
;
1650 if (request_resource(parent
, res
) == 0)
1656 __setup("reserve=", reserve_setup
);
1659 * Check if the requested addr and size spans more than any slot in the
1660 * iomem resource tree.
1662 int iomem_map_sanity_check(resource_size_t addr
, unsigned long size
)
1664 struct resource
*p
= &iomem_resource
;
1668 read_lock(&resource_lock
);
1669 for (p
= p
->child
; p
; p
= r_next(NULL
, p
, &l
)) {
1671 * We can probably skip the resources without
1672 * IORESOURCE_IO attribute?
1674 if (p
->start
>= addr
+ size
)
1678 if (PFN_DOWN(p
->start
) <= PFN_DOWN(addr
) &&
1679 PFN_DOWN(p
->end
) >= PFN_DOWN(addr
+ size
- 1))
1682 * if a resource is "BUSY", it's not a hardware resource
1683 * but a driver mapping of such a resource; we don't want
1684 * to warn for those; some drivers legitimately map only
1685 * partial hardware resources. (example: vesafb)
1687 if (p
->flags
& IORESOURCE_BUSY
)
1690 printk(KERN_WARNING
"resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
1691 (unsigned long long)addr
,
1692 (unsigned long long)(addr
+ size
- 1),
1697 read_unlock(&resource_lock
);
1702 #ifdef CONFIG_STRICT_DEVMEM
1703 static int strict_iomem_checks
= 1;
1705 static int strict_iomem_checks
;
1709 * check if an address is reserved in the iomem resource tree
1710 * returns true if reserved, false if not reserved.
1712 bool iomem_is_exclusive(u64 addr
)
1714 struct resource
*p
= &iomem_resource
;
1717 int size
= PAGE_SIZE
;
1719 if (!strict_iomem_checks
)
1722 addr
= addr
& PAGE_MASK
;
1724 read_lock(&resource_lock
);
1725 for (p
= p
->child
; p
; p
= r_next(NULL
, p
, &l
)) {
1727 * We can probably skip the resources without
1728 * IORESOURCE_IO attribute?
1730 if (p
->start
>= addr
+ size
)
1735 * A resource is exclusive if IORESOURCE_EXCLUSIVE is set
1736 * or CONFIG_IO_STRICT_DEVMEM is enabled and the
1739 if ((p
->flags
& IORESOURCE_BUSY
) == 0)
1741 if (IS_ENABLED(CONFIG_IO_STRICT_DEVMEM
)
1742 || p
->flags
& IORESOURCE_EXCLUSIVE
) {
1747 read_unlock(&resource_lock
);
1752 struct resource_entry
*resource_list_create_entry(struct resource
*res
,
1755 struct resource_entry
*entry
;
1757 entry
= kzalloc(sizeof(*entry
) + extra_size
, GFP_KERNEL
);
1759 INIT_LIST_HEAD(&entry
->node
);
1760 entry
->res
= res
? res
: &entry
->__res
;
1765 EXPORT_SYMBOL(resource_list_create_entry
);
1767 void resource_list_free(struct list_head
*head
)
1769 struct resource_entry
*entry
, *tmp
;
1771 list_for_each_entry_safe(entry
, tmp
, head
, node
)
1772 resource_list_destroy_entry(entry
);
1774 EXPORT_SYMBOL(resource_list_free
);
1776 #ifdef CONFIG_DEVICE_PRIVATE
1777 static struct resource
*__request_free_mem_region(struct device
*dev
,
1778 struct resource
*base
, unsigned long size
, const char *name
)
1780 resource_size_t end
, addr
;
1781 struct resource
*res
;
1783 size
= ALIGN(size
, 1UL << PA_SECTION_SHIFT
);
1784 end
= min_t(unsigned long, base
->end
, (1UL << MAX_PHYSMEM_BITS
) - 1);
1785 addr
= end
- size
+ 1UL;
1787 for (; addr
> size
&& addr
>= base
->start
; addr
-= size
) {
1788 if (region_intersects(addr
, size
, 0, IORES_DESC_NONE
) !=
1793 res
= devm_request_mem_region(dev
, addr
, size
, name
);
1795 res
= request_mem_region(addr
, size
, name
);
1797 return ERR_PTR(-ENOMEM
);
1798 res
->desc
= IORES_DESC_DEVICE_PRIVATE_MEMORY
;
1802 return ERR_PTR(-ERANGE
);
1806 * devm_request_free_mem_region - find free region for device private memory
1808 * @dev: device struct to bind the resource to
1809 * @size: size in bytes of the device memory to add
1810 * @base: resource tree to look in
1812 * This function tries to find an empty range of physical address big enough to
1813 * contain the new resource, so that it can later be hotplugged as ZONE_DEVICE
1814 * memory, which in turn allocates struct pages.
1816 struct resource
*devm_request_free_mem_region(struct device
*dev
,
1817 struct resource
*base
, unsigned long size
)
1819 return __request_free_mem_region(dev
, base
, size
, dev_name(dev
));
1821 EXPORT_SYMBOL_GPL(devm_request_free_mem_region
);
1823 struct resource
*request_free_mem_region(struct resource
*base
,
1824 unsigned long size
, const char *name
)
1826 return __request_free_mem_region(NULL
, base
, size
, name
);
1828 EXPORT_SYMBOL_GPL(request_free_mem_region
);
1830 #endif /* CONFIG_DEVICE_PRIVATE */
1832 static int __init
strict_iomem(char *str
)
1834 if (strstr(str
, "relaxed"))
1835 strict_iomem_checks
= 0;
1836 if (strstr(str
, "strict"))
1837 strict_iomem_checks
= 1;
1841 static int iomem_fs_init_fs_context(struct fs_context
*fc
)
1843 return init_pseudo(fc
, DEVMEM_MAGIC
) ? 0 : -ENOMEM
;
1846 static struct file_system_type iomem_fs_type
= {
1848 .owner
= THIS_MODULE
,
1849 .init_fs_context
= iomem_fs_init_fs_context
,
1850 .kill_sb
= kill_anon_super
,
1853 static int __init
iomem_init_inode(void)
1855 static struct vfsmount
*iomem_vfs_mount
;
1856 static int iomem_fs_cnt
;
1857 struct inode
*inode
;
1860 rc
= simple_pin_fs(&iomem_fs_type
, &iomem_vfs_mount
, &iomem_fs_cnt
);
1862 pr_err("Cannot mount iomem pseudo filesystem: %d\n", rc
);
1866 inode
= alloc_anon_inode(iomem_vfs_mount
->mnt_sb
);
1867 if (IS_ERR(inode
)) {
1868 rc
= PTR_ERR(inode
);
1869 pr_err("Cannot allocate inode for iomem: %d\n", rc
);
1870 simple_release_fs(&iomem_vfs_mount
, &iomem_fs_cnt
);
1875 * Publish iomem revocation inode initialized.
1876 * Pairs with smp_load_acquire() in revoke_iomem().
1878 smp_store_release(&iomem_inode
, inode
);
1883 fs_initcall(iomem_init_inode
);
1885 __setup("iomem=", strict_iomem
);