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authorTejun Heo <tj@kernel.org>2013-09-11 22:29:07 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-26 15:30:22 -0700
commitcb26a311578e67769e92a39a0a63476533cb7e12 (patch)
tree13a1c59bdf23abdb063d1bc4a8cc1679e36dcd38 /lib/kobject.c
parent4b30ee58ee64c64f59fd876e4afa6ed82caef3a4 (diff)
downloadlinux-linaro-stable-cb26a311578e67769e92a39a0a63476533cb7e12.tar.gz
sysfs: drop kobj_ns_type handling
The way namespace tags are implemented in sysfs is more complicated than necessary. As each tag is a pointer value and required to be non-NULL under a namespace enabled parent, there's no need to record separately what type each tag is or where namespace is enabled. If multiple namespace types are needed, which currently aren't, we can simply compare the tag to a set of allowed tags in the superblock assuming that the tags, being pointers, won't have the same value across multiple types. Also, whether to filter by namespace tag or not can be trivially determined by whether the node has any tagged children or not. This patch rips out kobj_ns_type handling from sysfs. sysfs no longer cares whether specific type of namespace is enabled or not. If a sysfs_dirent has a non-NULL tag, the parent is marked as needing namespace filtering and the value is tested against the allowed set of tags for the superblock (currently only one but increasing this number isn't difficult) and the sysfs_dirent is ignored if it doesn't match. This removes most kobject namespace knowledge from sysfs proper which will enable proper separation and layering of sysfs. The namespace sanity checks in fs/sysfs/dir.c are replaced by the new sanity check in kobject_namespace(). As this is the only place ktype->namespace() is called for sysfs, this doesn't weaken the sanity check significantly. I omitted converting the sanity check in sysfs_do_create_link_sd(). While the check can be shifted to upper layer, mistakes there are well contained and should be easily visible anyway. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/kobject.c')
-rw-r--r--lib/kobject.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/lib/kobject.c b/lib/kobject.c
index 85fb3a161b21..e769ee3c2fb9 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -29,11 +29,14 @@
const void *kobject_namespace(struct kobject *kobj)
{
const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
+ const void *ns;
if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
return NULL;
- return kobj->ktype->namespace(kobj);
+ ns = kobj->ktype->namespace(kobj);
+ WARN_ON(!ns); /* @kobj in a namespace is required to have !NULL tag */
+ return ns;
}
/*