sysfs: consolidate sysfs_dirent creation functions

Currently there are four functions to create sysfs_dirent -
__sysfs_new_dirent(), sysfs_new_dirent(), __sysfs_make_dirent() and
sysfs_make_dirent().  Other than sysfs_make_dirent(), no function has
two users if calls to implement other functions are excluded.

This patch consolidates sysfs_dirent creation functions into the
following two.

* sysfs_new_dirent() : allocate and initialize
* sysfs_attach_dirent() : attach to sysfs_dirent hierarchy and/or
			  associate with dentry

This simplifies interface and gives callers more flexibility.  This is
in preparation of object reference simplification.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 50 insertions, 67 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 90bed5df254f..f16aa7e3eafc 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -85,10 +85,7 @@ static struct dentry_operations sysfs_dentry_ops = {
         .d_iput         = sysfs_d_iput,
 };
 
-/*
- * Allocates a new sysfs_dirent and links it to the parent sysfs_dirent
- */
-static struct sysfs_dirent * __sysfs_new_dirent(void * element)
+struct sysfs_dirent *sysfs_new_dirent(void *element, umode_t mode, int type)
 {
         struct sysfs_dirent * sd;
 
@@ -105,25 +102,25 @@ static struct sysfs_dirent * __sysfs_new_dirent(void * element)
         atomic_set(&sd->s_event, 1);
         INIT_LIST_HEAD(&sd->s_children);
         INIT_LIST_HEAD(&sd->s_sibling);
+
         sd->s_element = element;
+        sd->s_mode = mode;
+        sd->s_type = type;
 
         return sd;
 }
 
-static void __sysfs_list_dirent(struct sysfs_dirent *parent_sd,
-                              struct sysfs_dirent *sd)
+void sysfs_attach_dirent(struct sysfs_dirent *sd,
+                         struct sysfs_dirent *parent_sd, struct dentry *dentry)
 {
-        if (sd)
-                list_add(&sd->s_sibling, &parent_sd->s_children);
-}
+        if (dentry) {
+                sd->s_dentry = dentry;
+                dentry->d_fsdata = sysfs_get(sd);
+                dentry->d_op = &sysfs_dentry_ops;
+        }
 
-static struct sysfs_dirent * sysfs_new_dirent(struct sysfs_dirent *parent_sd,
-                                                void * element)
-{
-        struct sysfs_dirent *sd;
-        sd = __sysfs_new_dirent(element);
-        __sysfs_list_dirent(parent_sd, sd);
-        return sd;
+        if (parent_sd)
+                list_add(&sd->s_sibling, &parent_sd->s_children);
 }
 
 /*
@@ -151,39 +148,6 @@ int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
         return 0;
 }
 
-
-static struct sysfs_dirent *
-__sysfs_make_dirent(struct dentry *dentry, void *element, mode_t mode, int type)
-{
-        struct sysfs_dirent * sd;
-
-        sd = __sysfs_new_dirent(element);
-        if (!sd)
-                goto out;
-
-        sd->s_mode = mode;
-        sd->s_type = type;
-        sd->s_dentry = dentry;
-        if (dentry) {
-                dentry->d_fsdata = sysfs_get(sd);
-                dentry->d_op = &sysfs_dentry_ops;
-        }
-
-out:
-        return sd;
-}
-
-int sysfs_make_dirent(struct sysfs_dirent * parent_sd, struct dentry * dentry,
-                        void * element, umode_t mode, int type)
-{
-        struct sysfs_dirent *sd;
-
-        sd = __sysfs_make_dirent(dentry, element, mode, type);
-        __sysfs_list_dirent(parent_sd, sd);
-
-        return sd ? 0 : -ENOMEM;
-}
-
 static int init_dir(struct inode * inode)
 {
         inode->i_op = &sysfs_dir_inode_operations;
@@ -227,10 +191,11 @@ static int create_dir(struct kobject *kobj, struct dentry *parent,
         if (sysfs_dirent_exist(parent->d_fsdata, name))
                 goto out_dput;
 
-        error = sysfs_make_dirent(parent->d_fsdata, dentry, kobj, mode,
-                                  SYSFS_DIR);
-        if (error)
+        error = -ENOMEM;
+        sd = sysfs_new_dirent(kobj, mode, SYSFS_DIR);
+        if (!sd)
                 goto out_drop;
+        sysfs_attach_dirent(sd, parent->d_fsdata, dentry);
 
         error = sysfs_create(dentry, mode, init_dir);
         if (error)
@@ -245,7 +210,6 @@ static int create_dir(struct kobject *kobj, struct dentry *parent,
         goto out_dput;
 
  out_sput:
-        sd = dentry->d_fsdata;
         list_del_init(&sd->s_sibling);
         sysfs_put(sd);
  out_drop:
@@ -557,13 +521,16 @@ static int sysfs_dir_open(struct inode *inode, struct file *file)
 {
         struct dentry * dentry = file->f_path.dentry;
         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
+        struct sysfs_dirent * sd;
 
         mutex_lock(&dentry->d_inode->i_mutex);
-        file->private_data = sysfs_new_dirent(parent_sd, NULL);
+        sd = sysfs_new_dirent(NULL, 0, 0);
+        if (sd)
+                sysfs_attach_dirent(sd, parent_sd, NULL);
         mutex_unlock(&dentry->d_inode->i_mutex);
 
-        return file->private_data ? 0 : -ENOMEM;
-
+        file->private_data = sd;
+        return sd ? 0 : -ENOMEM;
 }
 
 static int sysfs_dir_close(struct inode *inode, struct file *file)
@@ -736,9 +703,10 @@ struct dentry *sysfs_create_shadow_dir(struct kobject *kobj)
         if (!shadow)
                 goto nomem;
 
-        sd = __sysfs_make_dirent(shadow, kobj, inode->i_mode, SYSFS_DIR);
+        sd = sysfs_new_dirent(kobj, inode->i_mode, SYSFS_DIR);
         if (!sd)
                 goto nomem;
+        sysfs_attach_dirent(sd, NULL, shadow);
 
         d_instantiate(shadow, igrab(inode));
         inc_nlink(inode);
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index b502c7197ec0..fd4b6dc03d2d 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -444,14 +444,25 @@ int sysfs_add_file(struct dentry * dir, const struct attribute * attr, int type)
 {
         struct sysfs_dirent * parent_sd = dir->d_fsdata;
         umode_t mode = (attr->mode & S_IALLUGO) | S_IFREG;
-        int error = -EEXIST;
+        struct sysfs_dirent *sd;
+        int error = 0;
 
         mutex_lock(&dir->d_inode->i_mutex);
-        if (!sysfs_dirent_exist(parent_sd, attr->name))
-                error = sysfs_make_dirent(parent_sd, NULL, (void *)attr,
-                                          mode, type);
-        mutex_unlock(&dir->d_inode->i_mutex);
 
+        if (sysfs_dirent_exist(parent_sd, attr->name)) {
+                error = -EEXIST;
+                goto out_unlock;
+        }
+
+        sd = sysfs_new_dirent((void *)attr, mode, type);
+        if (!sd) {
+                error = -ENOMEM;
+                goto out_unlock;
+        }
+        sysfs_attach_dirent(sd, parent_sd, NULL);
+
+ out_unlock:
+        mutex_unlock(&dir->d_inode->i_mutex);
         return error;
 }
 
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index b463f17f6638..d96bb9cbc9d4 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -49,6 +49,7 @@ static int sysfs_add_link(struct dentry * parent, const char * name, struct kobj
 {
         struct sysfs_dirent * parent_sd = parent->d_fsdata;
         struct sysfs_symlink * sl;
+        struct sysfs_dirent * sd;
         int error;
 
         error = -ENOMEM;
@@ -63,10 +64,10 @@ static int sysfs_add_link(struct dentry * parent, const char * name, struct kobj
         strcpy(sl->link_name, name);
         sl->target_kobj = kobject_get(target);
 
-        error = sysfs_make_dirent(parent_sd, NULL, sl, S_IFLNK|S_IRWXUGO,
-                                SYSFS_KOBJ_LINK);
-        if (error)
+        sd = sysfs_new_dirent(sl, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
+        if (!sd)
                 goto err_out;
+        sysfs_attach_dirent(sd, parent_sd, NULL);
 
         return 0;
 
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index f4fdbbffd571..f8f49cc5c852 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -20,8 +20,11 @@ extern int sysfs_create(struct dentry *, int mode, int (*init)(struct inode *));
 
 extern void release_sysfs_dirent(struct sysfs_dirent * sd);
 extern int sysfs_dirent_exist(struct sysfs_dirent *, const unsigned char *);
-extern int sysfs_make_dirent(struct sysfs_dirent *, struct dentry *, void *,
-                                umode_t, int);
+extern struct sysfs_dirent *sysfs_new_dirent(void *element, umode_t mode,
+                                             int type);
+extern void sysfs_attach_dirent(struct sysfs_dirent *sd,
+                                struct sysfs_dirent *parent_sd,
+                                struct dentry *dentry);
 
 extern int sysfs_add_file(struct dentry *, const struct attribute *, int);
 extern int sysfs_hash_and_remove(struct dentry * dir, const char * name);