[PATCH 11/34] sysfs, kernfs: introduce kernfs_create_file[_ns]()

Tejun Heo
2013-11-28T19:55:29Z

Introduce kernfs interface to create a file which takes and returns
sysfs_dirents.

The actual file creation part is separated out from
sysfs_add_file_mode_ns() into kernfs_create_file_ns(). The former now
only decides the kernfs_ops to use and the file's size and invokes the
latter.

This patch doesn't introduce behavior changes.

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

Signed-off-by: Tejun Heo <tj@kernel.org>
---
fs/sysfs/file.c | 53 +++++++++++++++++++++++++++++++++++++++-----------
include/linux/kernfs.h | 18 +++++++++++++++++
2 files changed, 60 insertions(+), 11 deletions(-)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index e2ce674..69cca0f 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -912,14 +912,11 @@ static const struct kernfs_ops sysfs_bin_kfops_rw = {

int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
const struct attribute *attr, bool is_bin,
- umode_t amode, const void *ns)
+ umode_t mode, const void *ns)
{
- umode_t mode = (amode & S_IALLUGO) | S_IFREG;
const struct kernfs_ops *ops;
- struct sysfs_addrm_cxt acxt;
struct sysfs_dirent *sd;
loff_t size;
- int rc;

if (!is_bin) {
struct kobject *kobj = dir_sd->priv;
@@ -956,14 +953,47 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
size = battr->size;
}

- sd = sysfs_new_dirent(attr->name, mode, SYSFS_KOBJ_ATTR);
+ sd = kernfs_create_file_ns(dir_sd, attr->name, mode, size,
+ ops, (void *)attr, ns);
+ if (IS_ERR(sd)) {
+ if (PTR_ERR(sd) == -EEXIST)
+ sysfs_warn_dup(dir_sd, attr->name);
+ return PTR_ERR(sd);
+ }
+ return 0;
+}
+
+/**
+ * kernfs_create_file_ns - create a file
+ * @parent: directory to create the file in
+ * @name: name of the file
+ * @mode: mode of the file
+ * @size: size of the file
+ * @ops: kernfs operations for the file
+ * @priv: private data for the file
+ * @ns: optional namespace tag of the file
+ *
+ * Returns the created node on success, ERR_PTR() value on error.
+ */
+struct sysfs_dirent *kernfs_create_file_ns(struct sysfs_dirent *parent,
+ const char *name,
+ umode_t mode, loff_t size,
+ const struct kernfs_ops *ops,
+ void *priv, const void *ns)
+{
+ struct sysfs_addrm_cxt acxt;
+ struct sysfs_dirent *sd;
+ int rc;
+
+ sd = sysfs_new_dirent(name, (mode & S_IALLUGO) | S_IFREG,
+ SYSFS_KOBJ_ATTR);
if (!sd)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);

sd->s_attr.ops = ops;
sd->s_attr.size = size;
sd->s_ns = ns;
- sd->priv = (void *)attr;
+ sd->priv = priv;
sysfs_dirent_init_lockdep(sd);

/*
@@ -977,13 +1007,14 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
sd->s_flags |= SYSFS_FLAG_HAS_MMAP;

sysfs_addrm_start(&acxt);
- rc = sysfs_add_one(&acxt, sd, dir_sd);
+ rc = __sysfs_add_one(&acxt, sd, parent);
sysfs_addrm_finish(&acxt);

- if (rc)
+ if (rc) {
sysfs_put(sd);
-
- return rc;
+ return ERR_PTR(rc);
+ }
+ return sd;
}

int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 97c6c0f..d0912cf 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -64,6 +64,11 @@ struct kernfs_ops {
struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
const char *name, void *priv,
const void *ns);
+struct sysfs_dirent *kernfs_create_file_ns(struct sysfs_dirent *parent,
+ const char *name,
+ umode_t mode, loff_t size,
+ const struct kernfs_ops *ops,
+ void *priv, const void *ns);
struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
const char *name,
struct sysfs_dirent *target);
@@ -83,6 +88,12 @@ kernfs_create_dir_ns(struct sysfs_dirent *parent, const char *name, void *priv,
{ return ERR_PTR(-ENOSYS); }

static inline struct sysfs_dirent *
+kernfs_create_file_ns(struct sysfs_dirent *parent, const char *name,
+ umode_t mode, loff_t size, const struct kernfs_ops *ops,
+ 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); }
@@ -112,6 +123,13 @@ kernfs_create_dir(struct sysfs_dirent *parent, const char *name, void *priv)
return kernfs_create_dir_ns(parent, name, priv, NULL);
}

+static inline struct sysfs_dirent *
+kernfs_create_file(struct sysfs_dirent *parent, const char *name, umode_t mode,
+ loff_t size, const struct kernfs_ops *ops, void *priv)
+{
+ return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
+}
+
static inline int kernfs_remove_by_name(struct sysfs_dirent *parent,
const char *name)
{
--
1.8.4.2