sysfs: remove sysfs_addrm_cxt->parent_sd

sysfs_addrm_start/finish() enclose sysfs_dirent additions and
deletions and sysfs_addrm_cxt is used to record information necessary
to finish the operations.  Currently, sysfs_addrm_start() takes
@parent_sd, records it in sysfs_addrm_cxt, and assumes that all
operations in the block are performed under that @parent_sd.

This assumption has been fine until now but we want to make some
operations behave recursively and, while having @parent_sd recorded in
sysfs_addrm_cxt doesn't necessarily prevents that, it becomes
confusing.

This patch removes sysfs_addrm_cxt->parent_sd and makes
sysfs_add_one() take an explicit @parent_sd parameter.  Note that
sysfs_remove_one() doesn't need the extra argument as its parent is
always known from the target @sd.

While at it, add __acquires/releases() notations to
sysfs_addrm_start/finish() respectively.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 88c8bc5..22ea2f5 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -53,11 +53,11 @@
 	sd->s_symlink.target_sd = target_sd;
 	target_sd = NULL;	/* reference is now owned by the symlink */
 
-	sysfs_addrm_start(&acxt, parent_sd);
+	sysfs_addrm_start(&acxt);
 	if (warn)
-		error = sysfs_add_one(&acxt, sd);
+		error = sysfs_add_one(&acxt, sd, parent_sd);
 	else
-		error = __sysfs_add_one(&acxt, sd);
+		error = __sysfs_add_one(&acxt, sd, parent_sd);
 	sysfs_addrm_finish(&acxt);
 
 	if (error)