[RFC][PATCH v2 08/11] sysfs: introduce new interface sysfs_get_kobject

[Lin Ming <ming.m.lin@intel.com>]

Need this interface in the later sysfs pmu lookup.

struct kobject *sysfs_get_kobject(struct file *file);
Return the relative kobject of the sysfs file.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
---
 fs/sysfs/file.c       |   15 +++++++++++++++
 include/linux/sysfs.h |    2 ++
 2 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index e222b25..0c5d6fe 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -748,6 +748,21 @@ int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
 }
 EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
 
+struct kobject *sysfs_get_kobject(struct file *file)
+{
+	struct sysfs_dirent *attr_sd;
+	struct kobject *kobj;
+
+	if (!file)
+		return NULL;
+	if (file->f_op != &sysfs_file_operations)
+		return NULL;
+
+	attr_sd = file->f_path.dentry->d_fsdata;
+	kobj = attr_sd->s_parent->s_dir.kobj;
+
+	return kobj;
+}
 
 EXPORT_SYMBOL_GPL(sysfs_create_file);
 EXPORT_SYMBOL_GPL(sysfs_remove_file);
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index f0496b3..5954234 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -121,6 +121,8 @@ struct sysfs_dirent;
 
 #ifdef CONFIG_SYSFS
 
+struct kobject *sysfs_get_kobject(struct file *file);
+
 int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
 			    void *data, struct module *owner);