sysfs: make sysfs_add/remove_one() call link/unlink_sibling() implictly

When adding or removing a sysfs_dirent, the user used to be required
to call link/unlink separately.  It was for two reasons - code looked
like that before sysfs_addrm_cxt conversion and to avoid looping
through parent_sd->children list twice during removal.

Performance optimization during removal just isn't worth it.  Make
sysfs_add/remove_one() call sysfs_link/unlink_sibing() implicitly.
This makes code simpler albeit slightly less efficient.  This change
doesn't introduce any noticeable behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index b21d11b..ea0e494 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -405,10 +405,8 @@
 
 	sysfs_addrm_start(&acxt, dir_sd);
 
-	if (!sysfs_find_dirent(dir_sd, attr->name)) {
+	if (!sysfs_find_dirent(dir_sd, attr->name))
 		sysfs_add_one(&acxt, sd);
-		sysfs_link_sibling(sd);
-	}
 
 	if (!sysfs_addrm_finish(&acxt)) {
 		sysfs_put(sd);