[PATCH 02/34] sysfs, kernfs: introduce kernfs_create_dir[_ns]()

Tejun Heo
2013-11-28T19:55:08Z

Introduce kernfs interface to manipulate a directory which takes and
returns sysfs_dirents.

create_dir() is renamed to kernfs_create_dir_ns() and its argumantes
and return value are updated. create_dir() usages are replaced with
kernfs_create_dir_ns() and sysfs_create_subdir() usages are replaced
with kernfs_create_dir(). Dup warnings are handled explicitly by
sysfs users of the kernfs interface.

sysfs_enable_ns() is renamed to kernfs_enable_ns().

This patch doesn't introduce any behavior changes.

v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.

v3: kernfs_enable_ns() added.

v4: Refreshed on top of "sysfs: drop kobj_ns_type handling, take #2"
so that this patch removes sysfs_enable_ns().

Signed-off-by: Tejun Heo <tj@kernel.org>
---
fs/sysfs/dir.c | 54 ++++++++++++++++++++++++++++----------------------
fs/sysfs/group.c | 9 ++++++---
fs/sysfs/sysfs.h | 3 ---
include/linux/kernfs.h | 17 ++++++++++++++++
include/linux/sysfs.h | 6 ------
lib/kobject.c | 2 +-
6 files changed, 54 insertions(+), 37 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index aeb08bd..cfbf409 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -666,9 +666,18 @@ struct sysfs_dirent *sysfs_get_dirent_ns(struct sysfs_dirent *parent_sd,
}
EXPORT_SYMBOL_GPL(sysfs_get_dirent_ns);

-static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
- const char *name, const void *ns,
- struct sysfs_dirent **p_sd)
+/**
+ * kernfs_create_dir_ns - create a directory
+ * @parent: parent in which to create a new directory
+ * @name: name of the new directory
+ * @priv: opaque data associated with the new directory
+ * @ns: optional namespace tag of the directory
+ *
+ * Returns the created node on success, ERR_PTR() value on failure.
+ */
+struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
+ const char *name, void *priv,
+ const void *ns)
{
umode_t mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
struct sysfs_addrm_cxt acxt;
@@ -678,28 +687,21 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
/* allocate */
sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
if (!sd)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);

sd->s_ns = ns;
- sd->priv = kobj;
+ sd->priv = priv;

/* link in */
sysfs_addrm_start(&acxt);
- rc = sysfs_add_one(&acxt, sd, parent_sd);
+ rc = __sysfs_add_one(&acxt, sd, parent);
sysfs_addrm_finish(&acxt);

- if (rc == 0)
- *p_sd = sd;
- else
- sysfs_put(sd);
+ if (!rc)
+ return sd;

- return rc;
-}
-
-int sysfs_create_subdir(struct kobject *kobj, const char *name,
- struct sysfs_dirent **p_sd)
-{
- return create_dir(kobj, kobj->sd, name, NULL, p_sd);
+ sysfs_put(sd);
+ return ERR_PTR(rc);
}

/**
@@ -710,7 +712,6 @@ int sysfs_create_subdir(struct kobject *kobj, const char *name,
int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
{
struct sysfs_dirent *parent_sd, *sd;
- int error = 0;

BUG_ON(!kobj);

@@ -722,10 +723,15 @@ int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
if (!parent_sd)
return -ENOENT;

- error = create_dir(kobj, parent_sd, kobject_name(kobj), ns, &sd);
- if (!error)
- kobj->sd = sd;
- return error;
+ sd = kernfs_create_dir_ns(parent_sd, kobject_name(kobj), kobj, ns);
+ if (IS_ERR(sd)) {
+ if (PTR_ERR(sd) == -EEXIST)
+ sysfs_warn_dup(parent_sd, kobject_name(kobj));
+ return PTR_ERR(sd);
+ }
+
+ kobj->sd = sd;
+ return 0;
}

static struct dentry *sysfs_lookup(struct inode *dir, struct dentry *dentry,
@@ -1005,14 +1011,14 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
}

/**
- * sysfs_enable_ns - enable namespace under a directory
+ * kernfs_enable_ns - enable namespace under a directory
* @sd: directory of interest, should be empty
*
* This is to be called right after @sd is created to enable namespace
* under it. All children of @sd must have non-NULL namespace tags and
* only the ones which match the super_block's tag will be visible.
*/
-void sysfs_enable_ns(struct sysfs_dirent *sd)
+void kernfs_enable_ns(struct sysfs_dirent *sd)
{
WARN_ON_ONCE(sysfs_type(sd) != SYSFS_DIR);
WARN_ON_ONCE(!RB_EMPTY_ROOT(&sd->s_dir.children));
diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c
index 4bd9973..065689d 100644
--- a/fs/sysfs/group.c
+++ b/fs/sysfs/group.c
@@ -101,9 +101,12 @@ static int internal_create_group(struct kobject *kobj, int update,
return -EINVAL;
}
if (grp->name) {
- error = sysfs_create_subdir(kobj, grp->name, &sd);
- if (error)
- return error;
+ sd = kernfs_create_dir(kobj->sd, grp->name, kobj);
+ if (IS_ERR(sd)) {
+ if (PTR_ERR(sd) == -EEXIST)
+ sysfs_warn_dup(kobj->sd, grp->name);
+ return PTR_ERR(sd);
+ }
} else
sd = kobj->sd;
sysfs_get(sd);
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index a6f3fa3..9ac234e 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -179,9 +179,6 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type);

void release_sysfs_dirent(struct sysfs_dirent *sd);

-int sysfs_create_subdir(struct kobject *kobj, const char *name,
- struct sysfs_dirent **p_sd);
-
static inline struct sysfs_dirent *__sysfs_get(struct sysfs_dirent *sd)
{
if (sd) {
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 8cb6738..e8b73d4 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -17,6 +17,9 @@ struct sysfs_dirent;

#ifdef CONFIG_SYSFS

+struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
+ const char *name, void *priv,
+ const void *ns);
struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
const char *name,
struct sysfs_dirent *target);
@@ -25,11 +28,17 @@ int kernfs_remove_by_name_ns(struct sysfs_dirent *parent, const char *name,
const void *ns);
int kernfs_rename_ns(struct sysfs_dirent *sd, struct sysfs_dirent *new_parent,
const char *new_name, const void *new_ns);
+void kernfs_enable_ns(struct sysfs_dirent *sd);
int kernfs_setattr(struct sysfs_dirent *sd, const struct iattr *iattr);

#else /* CONFIG_SYSFS */

static inline struct sysfs_dirent *
+kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv,
+ const void *ns)
+{ return ERR_PTR(-ENOSYS); }
+
+static inline struct sysfs_dirent *
kernfs_create_link(struct sysfs_dirent *parent, const char *name,
struct sysfs_dirent *target)
{ return ERR_PTR(-ENOSYS); }
@@ -45,12 +54,20 @@ static inline int kernfs_rename_ns(struct sysfs_dirent *sd,
const char *new_name, const void *new_ns)
{ return -ENOSYS; }

+static inline void kernfs_enable_ns(struct sysfs_dirent *sd) { }
+
static inline int kernfs_setattr(struct sysfs_dirent *sd,
const struct iattr *iattr)
{ return -ENOSYS; }

#endif /* CONFIG_SYSFS */

+static inline struct sysfs_dirent *
+kernfs_create_dir(struct sysfs_dirent *parent, const char *name, void *priv)
+{
+ return kernfs_create_dir_ns(parent, name, priv, NULL);
+}
+
static inline int kernfs_remove_by_name(struct sysfs_dirent *parent,
const char *name)
{
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index e17381a..2bc735d 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -219,8 +219,6 @@ int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *target,
void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
const char *name);

-void sysfs_enable_ns(struct sysfs_dirent *sd);
-
int __must_check sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp);
int __must_check sysfs_create_groups(struct kobject *kobj,
@@ -354,10 +352,6 @@ static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
{
}

-static inline void sysfs_enable_ns(struct sysfs_dirent *sd)
-{
-}
-
static inline int sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp)
{
diff --git a/lib/kobject.c b/lib/kobject.c
index 16e9335..b8d848f 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -94,7 +94,7 @@ static int create_dir(struct kobject *kobj)
BUG_ON(ops->type >= KOBJ_NS_TYPES);
BUG_ON(!kobj_ns_type_registered(ops->type));

- sysfs_enable_ns(kobj->sd);
+ kernfs_enable_ns(kobj->sd);
}

return 0;
--
1.8.4.2