From 66f1207bce10fd80ee8ce99b67d617644612f05e Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Thu, 11 Mar 2010 17:01:09 -0700 Subject: resources: add interfaces that return conflict information 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 Signed-off-by: Jesse Barnes --- kernel/resource.c | 44 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 37 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/resource.c b/kernel/resource.c index 2d5be5d9bf5..9c358e26353 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -219,19 +219,34 @@ void release_child_resources(struct resource *r) } /** - * request_resource - request and reserve an I/O or memory resource + * 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, negative error code on error. + * Returns 0 for success, conflict resource on error. */ -int request_resource(struct resource *root, struct resource *new) +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 + * @new: resource descriptor desired by caller + * + * Returns 0 for success, negative error code on error. + */ +int request_resource(struct resource *root, struct resource *new) +{ + struct resource *conflict; + + 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; } -- cgit v1.2.3-70-g09d2