sysfs, kernfs: introduce kernfs_create_file[_ns]()

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index e2ce6743113a4fcbea918eca9acfa051d89ed44b..69cca0f4ccf39319d4aec56e5d15fc498069107a 100644 (file)
--- 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 97c6c0f91325c28b9373937cfe8ac25c9ba9da85..d0912cf02087e49e64dddf6f1254f8ed0886ae6c 100644 (file)
--- 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);
@@ -82,6 +87,12 @@ 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_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)
@@ -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)
 {