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authorTejun Heo <tj@kernel.org>2013-11-28 14:54:40 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-11-29 18:10:48 -0800
commitba7443bc656e5236c316b2acacc8b551f872910f (patch)
tree08b9a7a0504ae77abc634419167958ce4e6c4e64 /include
parent061447a496b915f1dc8f8c645c6825f856d2bbac (diff)
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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')
-rw-r--r--include/linux/kernfs.h13
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)