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Resource handling: add 'insert_resource_expand_to_fit()' function 

Not used anywhere yet, but this complements the existing plain
'insert_resource()' functionality with a version that can expand the
resource we are adding in order to fix up any conflicts it has with
existing resources.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2008-08-29 20:18:31 -07:00
parent 00aeb429a0
commit bef69ea0dc
2 changed files with 64 additions and 25 deletions
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1
include/linux/ioport.h
View File

@ -109,6 +109,7 @@ extern struct resource iomem_resource;
extern int request_resource(struct resource *root, struct resource *new);
extern int release_resource(struct resource *new);
extern int insert_resource(struct resource *parent, struct resource *new);
extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);
extern int allocate_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
resource_size_t max, resource_size_t align,

88
kernel/resource.c
View File

@ -362,35 +362,21 @@ int allocate_resource(struct resource *root, struct resource *new,
EXPORT_SYMBOL(allocate_resource);
/**
* insert_resource - Inserts a resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
* Returns 0 on success, -EBUSY if the resource can't be inserted.
*
* This function is equivalent to request_resource when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become children of
* the new resource.
/*
* Insert a resource into the resource tree. If successful, return NULL,
* otherwise return the conflicting resource (compare to __request_resource())
*/
int insert_resource(struct resource *parent, struct resource *new)
static struct resource * __insert_resource(struct resource *parent, struct resource *new)
{
int result;
struct resource *first, *next;
write_lock(&resource_lock);
for (;; parent = first) {
result = 0;
first = __request_resource(parent, new);
if (!first)
goto out;
return first;
result = -EBUSY;
if (first == parent)
goto out;
return first;
if ((first->start > new->start) || (first->end < new->end))
break;
@ -401,15 +387,13 @@ int insert_resource(struct resource *parent, struct resource *new)
for (next = first; ; next = next->sibling) {
/* Partial overlap? Bad, and unfixable */
if (next->start < new->start || next->end > new->end)
goto out;
return next;
if (!next->sibling)
break;
if (next->sibling->start > new->end)
break;
}
result = 0;
new->parent = parent;
new->sibling = next->sibling;
new->child = first;
@ -426,10 +410,64 @@ int insert_resource(struct resource *parent, struct resource *new)
next = next->sibling;
next->sibling = new;
}
return NULL;
}
out:
/**
* insert_resource - Inserts a resource in the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
* Returns 0 on success, -EBUSY if the resource can't be inserted.
*
* This function is equivalent to request_resource when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become children of
* the new resource.
*/
int insert_resource(struct resource *parent, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __insert_resource(parent, new);
write_unlock(&resource_lock);
return conflict ? -EBUSY : 0;
}
/**
* insert_resource_expand_to_fit - Insert a resource into the resource tree
* @parent: parent of the new resource
* @new: new resource to insert
*
* Insert a resource into the resource tree, possibly expanding it in order
* to make it encompass any conflicting resources.
*/
void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
{
if (new->parent)
return;
write_lock(&resource_lock);
for (;;) {
struct resource *conflict;
conflict = __insert_resource(root, new);
if (!conflict)
break;
if (conflict == root)
break;
/* Ok, expand resource to cover the conflict, then try again .. */
if (conflict->start < new->start)
new->start = conflict->start;
if (conflict->end > new->end)
new->end = conflict->end;
printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
}
write_unlock(&resource_lock);
return result;
}
/**