sysfs: implement sysfs_find_dirent() and sysfs_get_dirent()
Implement sysfs_find_dirent() and sysfs_get_dirent().
sysfs_dirent_exist() is replaced by sysfs_find_dirent(). These will
be used to make directory entries reclamiable.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index f2ea006..4762a9a 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -317,28 +317,55 @@
}
}
-/*
+/**
+ * sysfs_find_dirent - find sysfs_dirent with the given name
+ * @parent_sd: sysfs_dirent to search under
+ * @name: name to look for
*
- * Return -EEXIST if there is already a sysfs element with the same name for
- * the same parent.
+ * Look for sysfs_dirent with name @name under @parent_sd.
*
- * called with parent inode's i_mutex held
+ * LOCKING:
+ * mutex_lock(parent->i_mutex)
+ *
+ * RETURNS:
+ * Pointer to sysfs_dirent if found, NULL if not.
*/
-int sysfs_dirent_exist(struct sysfs_dirent *parent_sd,
- const unsigned char *new)
+struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd,
+ const unsigned char *name)
{
- struct sysfs_dirent * sd;
+ struct sysfs_dirent *sd;
- for (sd = parent_sd->s_children; sd; sd = sd->s_sibling) {
- if (sysfs_type(sd)) {
- if (strcmp(sd->s_name, new))
- continue;
- else
- return -EEXIST;
- }
- }
+ for (sd = parent_sd->s_children; sd; sd = sd->s_sibling)
+ if (sysfs_type(sd) && !strcmp(sd->s_name, name))
+ return sd;
+ return NULL;
+}
- return 0;
+/**
+ * sysfs_get_dirent - find and get sysfs_dirent with the given name
+ * @parent_sd: sysfs_dirent to search under
+ * @name: name to look for
+ *
+ * Look for sysfs_dirent with name @name under @parent_sd and get
+ * it if found.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ *
+ * RETURNS:
+ * Pointer to sysfs_dirent if found, NULL if not.
+ */
+struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
+ const unsigned char *name)
+{
+ struct sysfs_dirent *sd;
+
+ mutex_lock(&parent_sd->s_dentry->d_inode->i_mutex);
+ sd = sysfs_find_dirent(parent_sd, name);
+ sysfs_get(sd);
+ mutex_unlock(&parent_sd->s_dentry->d_inode->i_mutex);
+
+ return sd;
}
static int create_dir(struct kobject *kobj, struct dentry *parent,
@@ -382,7 +409,7 @@
/* link in */
error = -EEXIST;
- if (sysfs_dirent_exist(parent->d_fsdata, name))
+ if (sysfs_find_dirent(parent->d_fsdata, name))
goto out_iput;
sysfs_instantiate(dentry, inode);