configfs: Allow ->make_item() and ->make_group() to return detailed errors.

The configfs operations ->make_item() and ->make_group() currently
return a new item/group.  A return of NULL signifies an error.  Because
of this, -ENOMEM is the only return code bubbled up the stack.

Multiple folks have requested the ability to return specific error codes
when these operations fail.  This patch adds that ability by changing the
->make_item/group() ops to return ERR_PTR() values.  These errors are
bubbled up appropriately.  NULL returns are changed to -ENOMEM for
compatibility.

Also updated are the in-kernel users of configfs.

This is a rework of reverted commit 11c3b79218390a139f2d474ee1e983a672d5839a.

Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/Documentation/filesystems/configfs/configfs_example.c b/Documentation/filesystems/configfs/configfs_example.c
index 25151fd5c2c6..039648791701 100644
--- a/Documentation/filesystems/configfs/configfs_example.c
+++ b/Documentation/filesystems/configfs/configfs_example.c
@@ -279,7 +279,7 @@ static struct config_item *simple_children_make_item(struct config_group *group,
 
 	simple_child = kzalloc(sizeof(struct simple_child), GFP_KERNEL);
 	if (!simple_child)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 
 	config_item_init_type_name(&simple_child->item, name,
@@ -366,7 +366,7 @@ static struct config_group *group_children_make_group(struct config_group *group
 	simple_children = kzalloc(sizeof(struct simple_children),
 				  GFP_KERNEL);
 	if (!simple_children)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 
 	config_group_init_type_name(&simple_children->group, name,