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author | Tejun Heo <tj@kernel.org> | 2013-11-28 14:54:40 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-11-29 18:10:48 -0800 |
commit | ba7443bc656e5236c316b2acacc8b551f872910f (patch) | |
tree | 08b9a7a0504ae77abc634419167958ce4e6c4e64 /include/linux/kernfs.h | |
parent | 061447a496b915f1dc8f8c645c6825f856d2bbac (diff) | |
download | linux-stable-ba7443bc656e5236c316b2acacc8b551f872910f.tar.gz linux-stable-ba7443bc656e5236c316b2acacc8b551f872910f.tar.bz2 linux-stable-ba7443bc656e5236c316b2acacc8b551f872910f.zip |
sysfs, kernfs: implement kernfs_create/destroy_root()
There currently is single kernfs hierarchy in the whole system which
is used for sysfs. kernfs needs to support multiple hierarchies to
allow other users. This patch introduces struct kernfs_root which
serves as the root of each kernfs hierarchy and implements
kernfs_create/destroy_root().
* Each kernfs_root is associated with a root sd (sysfs_dentry). The
root is freed when the root sd is released and kernfs_destory_root()
simply invokes kernfs_remove() on the root sd. sysfs_remove_one()
is updated to handle release of the root sd. Note that ps_iattr
update in sysfs_remove_one() is trivially updated for readability.
* Root sd's are now dynamically allocated using sysfs_new_dirent().
Update sysfs_alloc_ino() so that it gives out ino from 1 so that the
root sd still gets ino 1.
* While kernfs currently only points to the root sd, it'll soon grow
fields which are specific to each hierarchy. As determining a given
sd's root will be necessary, sd->s_dir.root is added. This backlink
fits better as a separate field in sd; however, sd->s_dir is inside
union with space to spare, so use it to save space and provide
kernfs_root() accessor to determine the root sd.
* As hierarchies may be destroyed now, each mount needs to hold onto
the hierarchy it's attached to. Update sysfs_fill_super() and
sysfs_kill_sb() so that they get and put the kernfs_root
respectively.
* sysfs_root is replaced with kernfs_root which is dynamically created
by invoking kernfs_create_root() from sysfs_init().
This patch doesn't introduce any visible behavior changes.
v2: kernfs_create_root() forgot to set @sd->priv. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/kernfs.h')
-rw-r--r-- | include/linux/kernfs.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index fd8f574ef2fe..f75548b8ed7a 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -20,6 +20,11 @@ struct vm_area_struct; struct sysfs_dirent; +struct kernfs_root { + /* published fields */ + struct sysfs_dirent *sd; +}; + struct sysfs_open_file { /* published fields */ struct sysfs_dirent *sd; @@ -76,6 +81,9 @@ struct sysfs_dirent *kernfs_find_and_get_ns(struct sysfs_dirent *parent, void kernfs_get(struct sysfs_dirent *sd); void kernfs_put(struct sysfs_dirent *sd); +struct kernfs_root *kernfs_create_root(void *priv); +void kernfs_destroy_root(struct kernfs_root *root); + struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv, const void *ns); @@ -107,6 +115,11 @@ kernfs_find_and_get_ns(struct sysfs_dirent *parent, const char *name, static inline void kernfs_get(struct sysfs_dirent *sd) { } static inline void kernfs_put(struct sysfs_dirent *sd) { } +static inline struct kernfs_root *kernfs_create_root(void *priv) +{ return ERR_PTR(-ENOSYS); } + +static inline void kernfs_destroy_root(struct kernfs_root *root) { } + static inline struct sysfs_dirent * kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv, const void *ns) |