[PATCH 3/5] sysfs: reorganize sysfs_new_indoe() and sysfs_create()

Tejun Heo
2007-05-28T16:11:47Z

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>
---
fs/sysfs/dir.c | 130 ++++++++++++++++++++----------------------------------
fs/sysfs/inode.c | 108 ++++++++++++++++++++++++---------------------
fs/sysfs/mount.c | 18 ++++---
fs/sysfs/sysfs.h | 6 +-
4 files changed, 118 insertions(+), 144 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index a26e3db..bbf3525 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -191,39 +191,18 @@ int sysfs_dirent_exist(struct sysfs_dire
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 *ko
}

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 *ko
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 * ko
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 81460c5..3b2dc2a 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -132,62 +132,68 @@ static inline void set_inode_attr(struct
*/
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 c5fabfe..7f2779e 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -27,6 +27,7 @@ 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_ino = 1,
.s_iattr = NULL,
};
@@ -43,18 +44,19 @@ static int sysfs_fill_super(struct super
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 fc6aa86..143fdbe 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 *);
--
1.4.3.4