sysfs, kernfs: introduce kernfs_create_link()

Separate out kernfs symlink interface - kernfs_create_link() - which
takes and returns sysfs_dirents, from sysfs_do_create_link_sd().
sysfs_do_create_link_sd() now just determines the parent and target
sysfs_dirents and invokes the new interface and handles dup warning.

This patch doesn't introduce behavior changes.

v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 83e151ad0619..fe6290d41776 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -8,17 +8,26 @@
 #define __LINUX_KERNFS_H
 
 #include <linux/kernel.h>
+#include <linux/err.h>
 
 struct sysfs_dirent;
 
 #ifdef CONFIG_SYSFS
 
+struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
+                                        const char *name,
+                                        struct sysfs_dirent *target);
 void kernfs_remove(struct sysfs_dirent *sd);
 int kernfs_remove_by_name_ns(struct sysfs_dirent *parent, const char *name,
                              const void *ns);
 
 #else   /* CONFIG_SYSFS */
 
+static inline struct sysfs_dirent *
+kernfs_create_link(struct sysfs_dirent *parent, const char *name,
+                   struct sysfs_dirent *target)
+{ return ERR_PTR(-ENOSYS); }
+
 static inline void kernfs_remove(struct sysfs_dirent *sd) { }
 
 static inline int kernfs_remove_by_name_ns(struct sysfs_dirent *parent,