sysfs: reorganize sysfs_new_indoe() and sysfs_create()

Reorganize/clean up sysfs_new_inode() and sysfs_create().

* sysfs_init_inode() is separated out from sysfs_new_inode() and is
  responsible for basic initialization.
* sysfs_instantiate() replaces the last step of sysfs_create() and is
  responsible for dentry instantitaion.
* type-specific initialization is moved out to the callers.
* mode is specified only once when creating a sysfs_dirent.
* spurious list_del_init(&sd->s_sibling) dropped from create_dir()

This change is to

* prepare for inode allocation fix.
* separate alloc and init code for synchronization update.
* make dentry/inode initialization more flexible for later changes.

This patch doesn't introduce visible behavior change.

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

4 files changed, 118 insertions, 144 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index a26e3db8943..bbf3525fd22 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -191,39 +191,18 @@ int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
         return 0;
 }
 
-static int init_dir(struct inode * inode)
-{
-        inode->i_op = &sysfs_dir_inode_operations;
-        inode->i_fop = &sysfs_dir_operations;
-
-        /* directory inodes start off with i_nlink == 2 (for "." entry) */
-        inc_nlink(inode);
-        return 0;
-}
-
-static int init_file(struct inode * inode)
-{
-        inode->i_size = PAGE_SIZE;
-        inode->i_fop = &sysfs_file_operations;
-        return 0;
-}
-
-static int init_symlink(struct inode * inode)
-{
-        inode->i_op = &sysfs_symlink_inode_operations;
-        return 0;
-}
-
 static int create_dir(struct kobject *kobj, struct dentry *parent,
                       const char *name, struct dentry **p_dentry)
 {
         int error;
         umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
         struct dentry *dentry;
+        struct inode *inode;
         struct sysfs_dirent *sd;
 
         mutex_lock(&parent->d_inode->i_mutex);
 
+        /* allocate */
         dentry = lookup_one_len(name, parent, strlen(name));
         if (IS_ERR(dentry)) {
                 error = PTR_ERR(dentry);
@@ -231,7 +210,7 @@ static int create_dir(struct kobject *kobj, struct dentry *parent,
         }
 
         error = -EEXIST;
-        if (sysfs_dirent_exist(parent->d_fsdata, name))
+        if (dentry->d_inode)
                 goto out_dput;
 
         error = -ENOMEM;
@@ -240,19 +219,31 @@ static int create_dir(struct kobject *kobj, struct dentry *parent,
                 goto out_drop;
         sd->s_elem.dir.kobj = kobj;
 
-        error = sysfs_create(sd, dentry, mode, init_dir);
-        if (error)
+        inode = sysfs_new_inode(sd);
+        if (!inode)
                 goto out_sput;
 
+        inode->i_op = &sysfs_dir_inode_operations;
+        inode->i_fop = &sysfs_dir_operations;
+        /* directory inodes start off with i_nlink == 2 (for "." entry) */
+        inc_nlink(inode);
+
+        /* link in */
+        error = -EEXIST;
+        if (sysfs_dirent_exist(parent->d_fsdata, name))
+                goto out_iput;
+
+        sysfs_instantiate(dentry, inode);
         inc_nlink(parent->d_inode);
         sysfs_attach_dirent(sd, parent->d_fsdata, dentry);
 
         *p_dentry = dentry;
         error = 0;
-        goto out_dput;
+        goto out_unlock;        /* pin directory dentry in core */
 
+ out_iput:
+        iput(inode);
  out_sput:
-        list_del_init(&sd->s_sibling);
         sysfs_put(sd);
  out_drop:
         d_drop(dentry);
@@ -298,71 +289,46 @@ int sysfs_create_dir(struct kobject * kobj, struct dentry *shadow_parent)
         return error;
 }
 
-/* attaches attribute's sysfs_dirent to the dentry corresponding to the
- * attribute file
- */
-static int sysfs_attach_attr(struct sysfs_dirent * sd, struct dentry * dentry)
-{
-        struct attribute * attr = NULL;
-        struct bin_attribute * bin_attr = NULL;
-        int (* init) (struct inode *) = NULL;
-        int error = 0;
-
-        if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
-                bin_attr = sd->s_elem.bin_attr.bin_attr;
-                attr = &bin_attr->attr;
-        } else {
-                attr = sd->s_elem.attr.attr;
-                init = init_file;
-        }
-
-        error = sysfs_create(sd, dentry,
-                             (attr->mode & S_IALLUGO) | S_IFREG, init);
-        if (error)
-                return error;
-
-        if (bin_attr) {
-                dentry->d_inode->i_size = bin_attr->size;
-                dentry->d_inode->i_fop = &bin_fops;
-        }
-
-        sysfs_attach_dentry(sd, dentry);
-
-        return 0;
-}
-
-static int sysfs_attach_link(struct sysfs_dirent * sd, struct dentry * dentry)
-{
-        int err;
-
-        err = sysfs_create(sd, dentry, S_IFLNK|S_IRWXUGO, init_symlink);
-        if (!err)
-                sysfs_attach_dentry(sd, dentry);
-
-        return err;
-}
-
 static struct dentry * sysfs_lookup(struct inode *dir, struct dentry *dentry,
                                 struct nameidata *nd)
 {
         struct sysfs_dirent * parent_sd = dentry->d_parent->d_fsdata;
         struct sysfs_dirent * sd;
-        int err = 0;
+        struct inode *inode;
+        int found = 0;
 
         list_for_each_entry(sd, &parent_sd->s_children, s_sibling) {
-                if (sd->s_type & SYSFS_NOT_PINNED) {
-                        if (strcmp(sd->s_name, dentry->d_name.name))
-                                continue;
-
-                        if (sd->s_type & SYSFS_KOBJ_LINK)
-                                err = sysfs_attach_link(sd, dentry);
-                        else
-                                err = sysfs_attach_attr(sd, dentry);
+                if ((sd->s_type & SYSFS_NOT_PINNED) &&
+                    !strcmp(sd->s_name, dentry->d_name.name)) {
+                        found = 1;
                         break;
                 }
         }
 
-        return ERR_PTR(err);
+        /* no such entry */
+        if (!found)
+                return NULL;
+
+        /* attach dentry and inode */
+        inode = sysfs_new_inode(sd);
+        if (!inode)
+                return ERR_PTR(-ENOMEM);
+
+        /* initialize inode according to type */
+        if (sd->s_type & SYSFS_KOBJ_ATTR) {
+                inode->i_size = PAGE_SIZE;
+                inode->i_fop = &sysfs_file_operations;
+        } else if (sd->s_type & SYSFS_KOBJ_BIN_ATTR) {
+                struct bin_attribute *bin_attr = sd->s_elem.bin_attr.bin_attr;
+                inode->i_size = bin_attr->size;
+                inode->i_fop = &bin_fops;
+        } else if (sd->s_type & SYSFS_KOBJ_LINK)
+                inode->i_op = &sysfs_symlink_inode_operations;
+
+        sysfs_instantiate(dentry, inode);
+        sysfs_attach_dentry(sd, dentry);
+
+        return NULL;
 }
 
 const struct inode_operations sysfs_dir_inode_operations = {
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 6ad47c13b94..26d8503c899 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -133,62 +133,68 @@ static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
  */
 static struct lock_class_key sysfs_inode_imutex_key;
 
-struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent * sd)
+void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
 {
-        struct inode * inode = new_inode(sysfs_sb);
-        if (inode) {
-                inode->i_blocks = 0;
-                inode->i_mapping->a_ops = &sysfs_aops;
-                inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
-                inode->i_op = &sysfs_inode_operations;
-                inode->i_ino = sd->s_ino;
-                lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
-
-                if (sd->s_iattr) {
-                        /* sysfs_dirent has non-default attributes
-                         * get them for the new inode from persistent copy
-                         * in sysfs_dirent
-                         */
-                        set_inode_attr(inode, sd->s_iattr);
-                } else
-                        set_default_inode_attr(inode, mode);
-        }
+        inode->i_blocks = 0;
+        inode->i_mapping->a_ops = &sysfs_aops;
+        inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
+        inode->i_op = &sysfs_inode_operations;
+        inode->i_ino = sd->s_ino;
+        lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
+
+        if (sd->s_iattr) {
+                /* sysfs_dirent has non-default attributes
+                 * get them for the new inode from persistent copy
+                 * in sysfs_dirent
+                 */
+                set_inode_attr(inode, sd->s_iattr);
+        } else
+                set_default_inode_attr(inode, sd->s_mode);
+}
+
+/**
+ *      sysfs_new_inode - allocate new inode for sysfs_dirent
+ *      @sd: sysfs_dirent to allocate inode for
+ *
+ *      Allocate inode for @sd and initialize basics.
+ *
+ *      LOCKING:
+ *      Kernel thread context (may sleep).
+ *
+ *      RETURNS:
+ *      Pointer to allocated inode on success, NULL on failure.
+ */
+struct inode * sysfs_new_inode(struct sysfs_dirent *sd)
+{
+        struct inode *inode;
+
+        inode = new_inode(sysfs_sb);
+        if (inode)
+                sysfs_init_inode(sd, inode);
+
         return inode;
 }
 
-int sysfs_create(struct sysfs_dirent *sd, struct dentry *dentry, int mode,
-                 int (*init)(struct inode *))
+/**
+ *      sysfs_instantiate - instantiate dentry
+ *      @dentry: dentry to be instantiated
+ *      @inode: inode associated with @sd
+ *
+ *      Instantiate @dentry with @inode.
+ *
+ *      LOCKING:
+ *      None.
+ */
+void sysfs_instantiate(struct dentry *dentry, struct inode *inode)
 {
-        int error = 0;
-        struct inode * inode = NULL;
-        if (dentry) {
-                if (!dentry->d_inode) {
-                        if ((inode = sysfs_new_inode(mode, sd))) {
-                                if (dentry->d_parent && dentry->d_parent->d_inode) {
-                                        struct inode *p_inode = dentry->d_parent->d_inode;
-                                        p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
-                                }
-                                goto Proceed;
-                        }
-                        else 
-                                error = -ENOMEM;
-                } else
-                        error = -EEXIST;
-        } else 
-                error = -ENOENT;
-        goto Done;
-
- Proceed:
-        if (init)
-                error = init(inode);
-        if (!error) {
-                d_instantiate(dentry, inode);
-                if (S_ISDIR(mode))
-                        dget(dentry);  /* pin only directory dentry in core */
-        } else
-                iput(inode);
- Done:
-        return error;
+        BUG_ON(!dentry || dentry->d_inode);
+
+        if (dentry->d_parent && dentry->d_parent->d_inode) {
+                struct inode *p_inode = dentry->d_parent->d_inode;
+                p_inode->i_mtime = p_inode->i_ctime = CURRENT_TIME;
+        }
+
+        d_instantiate(dentry, inode);
 }
 
 /**
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 37ff9ffc55f..6d3a6249d21 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -29,6 +29,7 @@ static struct sysfs_dirent sysfs_root = {
         .s_sibling      = LIST_HEAD_INIT(sysfs_root.s_sibling),
         .s_children     = LIST_HEAD_INIT(sysfs_root.s_children),
         .s_type         = SYSFS_ROOT,
+        .s_mode         = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
         .s_iattr        = NULL,
         .s_ino          = 1,
 };
@@ -45,18 +46,19 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
         sb->s_time_gran = 1;
         sysfs_sb = sb;
 
-        inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
-                                 &sysfs_root);
-        if (inode) {
-                inode->i_op = &sysfs_dir_inode_operations;
-                inode->i_fop = &sysfs_dir_operations;
-                /* directory inodes start off with i_nlink == 2 (for "." entry) */
-                inc_nlink(inode);
-        } else {
+        inode = new_inode(sysfs_sb);
+        if (!inode) {
                 pr_debug("sysfs: could not get root inode\n");
                 return -ENOMEM;
         }
 
+        sysfs_init_inode(&sysfs_root, inode);
+
+        inode->i_op = &sysfs_dir_inode_operations;
+        inode->i_fop = &sysfs_dir_operations;
+        /* directory inodes start off with i_nlink == 2 (for "." entry) */
+        inc_nlink(inode);
+
         root = d_alloc_root(inode);
         if (!root) {
                 pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index fc6aa863b94..143fdbe56c1 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -57,9 +57,9 @@ extern struct vfsmount * sysfs_mount;
 extern struct kmem_cache *sysfs_dir_cachep;
 
 extern void sysfs_delete_inode(struct inode *inode);
-extern struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent *);
-extern int sysfs_create(struct sysfs_dirent *sd, struct dentry *dentry,
-                        int mode, int (*init)(struct inode *));
+extern void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode);
+extern struct inode * sysfs_new_inode(struct sysfs_dirent *sd);
+extern void sysfs_instantiate(struct dentry *dentry, struct inode *inode);
 
 extern void release_sysfs_dirent(struct sysfs_dirent * sd);
 extern int sysfs_dirent_exist(struct sysfs_dirent *, const unsigned char *);