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authorBjorn Helgaas <bjorn.helgaas@hp.com>2010-03-11 17:01:09 -0700
committerJesse Barnes <jbarnes@virtuousgeek.org>2010-03-23 13:33:50 -0700
commit66f1207bce10fd80ee8ce99b67d617644612f05e (patch)
tree3031bb74dce8c54af69dcd4aa7e566f40a5511ce /kernel
parent7c9e2b1c4784c6e574f69dbd904b2822f2e04d6e (diff)
downloadop-kernel-dev-66f1207bce10fd80ee8ce99b67d617644612f05e.zip
op-kernel-dev-66f1207bce10fd80ee8ce99b67d617644612f05e.tar.gz
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 <bjorn.helgaas@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/resource.c44
1 files changed, 37 insertions, 7 deletions
diff --git a/kernel/resource.c b/kernel/resource.c
index 2d5be5d..9c358e2 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;
}
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