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Commit bef69ea0 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 00aeb429

include/linux/ioport.h

+1 −0
Original line number Diff line number Diff line
@@ -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,

kernel/resource.c

+63 −25
Original line number Diff line number Diff line
@@ -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;

}



/**