diff options
author | Serge E. Hallyn <serue@us.ibm.com> | 2010-05-03 23:23:15 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-21 18:37:31 +0200 |
commit | be867b194a3ae3c680c29521287ae49b4d44d420 (patch) | |
tree | 1b3ad125d02603c6a9cc4bb8ae518695d7c6a66d /fs/sysfs | |
parent | driver core: Implement ns directory support for device classes. (diff) | |
download | linux-be867b194a3ae3c680c29521287ae49b4d44d420.tar.xz linux-be867b194a3ae3c680c29521287ae49b4d44d420.zip |
sysfs: Comment sysfs directory tagging logic
Add some in-line comments to explain the new infrastructure, which
was introduced to support sysfs directory tagging with namespaces.
I think an overall description someplace might be good too, but it
didn't really seem to fit into Documentation/filesystems/sysfs.txt,
which appears more geared toward users, rather than maintainers, of
sysfs.
(Tejun, please let me know if I can make anything clearer or failed
altogether to comment something that should be commented.)
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs')
-rw-r--r-- | fs/sysfs/dir.c | 8 | ||||
-rw-r--r-- | fs/sysfs/sysfs.h | 13 |
2 files changed, 20 insertions, 1 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index a63eb4ba7867..7e54bac8c4b0 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -614,6 +614,14 @@ int sysfs_create_subdir(struct kobject *kobj, const char *name, KOBJ_NS_TYPE_NONE, NULL, name, p_sd); } +/** + * sysfs_read_ns_type: return associated ns_type + * @kobj: the kobject being queried + * + * Each kobject can be tagged with exactly one namespace type + * (i.e. network or user). Return the ns_type associated with + * this object if any + */ static enum kobj_ns_type sysfs_read_ns_type(struct kobject *kobj) { const struct kobj_ns_type_operations *ops; diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 93847d54c2e3..6a13105b5594 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -58,7 +58,7 @@ struct sysfs_dirent { struct sysfs_dirent *s_sibling; const char *s_name; - const void *s_ns; + const void *s_ns; /* namespace tag */ union { struct sysfs_elem_dir s_dir; struct sysfs_elem_symlink s_symlink; @@ -82,6 +82,7 @@ struct sysfs_dirent { #define SYSFS_COPY_NAME (SYSFS_DIR | SYSFS_KOBJ_LINK) #define SYSFS_ACTIVE_REF (SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR) +/* identify any namespace tag on sysfs_dirents */ #define SYSFS_NS_TYPE_MASK 0xff00 #define SYSFS_NS_TYPE_SHIFT 8 @@ -93,6 +94,10 @@ static inline unsigned int sysfs_type(struct sysfs_dirent *sd) return sd->s_flags & SYSFS_TYPE_MASK; } +/* + * Return any namespace tags on this dirent. + * enum kobj_ns_type is defined in linux/kobject.h + */ static inline enum kobj_ns_type sysfs_ns_type(struct sysfs_dirent *sd) { return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT; @@ -123,6 +128,12 @@ struct sysfs_addrm_cxt { /* * mount.c */ + +/* + * Each sb is associated with a set of namespace tags (i.e. + * the network namespace of the task which mounted this sysfs + * instance). + */ struct sysfs_super_info { const void *ns[KOBJ_NS_TYPES]; }; |