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resources: add interfaces that return conflict information

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request_resource() and insert_resource() only return success or failure,
which no information about what existing resource conflicted with the
proposed new reservation.  This patch adds request_resource_conflict()
and insert_resource_conflict(), which return the conflicting resource.

Callers may use this for better error messages or to adjust the new
resource and retry the request.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Bjorn Helgaas 2010-03-11 17:01:09 -07:00 committed by Jesse Barnes
parent 7c9e2b1c47
commit 66f1207bce
2 changed files with 39 additions and 7 deletions
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2
include/linux/ioport.h
View File

@ -112,12 +112,14 @@ struct resource_list {
extern struct resource ioport_resource;
extern struct resource iomem_resource;
extern struct resource *request_resource_conflict(struct resource *root, struct resource *new);
extern int request_resource(struct resource *root, struct resource *new);
extern int release_resource(struct resource *new);
void release_child_resources(struct resource *new);
extern void reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
const char *name);
extern struct resource *insert_resource_conflict(struct resource *parent, 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,

44
kernel/resource.c
View File

@ -218,6 +218,23 @@ void release_child_resources(struct resource *r)
write_unlock(&resource_lock);
}
/**
* request_resource_conflict - request and reserve an I/O or memory resource
* @root: root resource descriptor
* @new: resource descriptor desired by caller
*
* Returns 0 for success, conflict resource on error.
*/
struct resource *request_resource_conflict(struct resource *root, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __request_resource(root, new);
write_unlock(&resource_lock);
return conflict;
}
/**
* request_resource - request and reserve an I/O or memory resource
* @root: root resource descriptor
@ -229,9 +246,7 @@ int request_resource(struct resource *root, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __request_resource(root, new);
write_unlock(&resource_lock);
conflict = request_resource_conflict(root, new);
return conflict ? -EBUSY : 0;
}
@ -474,25 +489,40 @@ static struct resource * __insert_resource(struct resource *parent, struct resou
}
/**
* insert_resource - Inserts a resource in the resource tree
* insert_resource_conflict - Inserts 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.
* Returns 0 on success, conflict resource if the resource can't be inserted.
*
* This function is equivalent to request_resource when no conflict
* This function is equivalent to request_resource_conflict 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 *insert_resource_conflict(struct resource *parent, struct resource *new)
{
struct resource *conflict;
write_lock(&resource_lock);
conflict = __insert_resource(parent, new);
write_unlock(&resource_lock);
return conflict;
}
/**
* 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.
*/
int insert_resource(struct resource *parent, struct resource *new)
{
struct resource *conflict;
conflict = insert_resource_conflict(parent, new);
return conflict ? -EBUSY : 0;
}