Revert "cgroup: add cgroup_subsys->css_e_css_changed()"

This reverts commit 56c807ba4e91f0980567b6a69de239677879b17f.

cgroup_subsys->css_e_css_changed() was supposed to be used by cgroup
writeback support; however, the change to per-inode cgroup association
made it unnecessary and the callback doesn't have any user.  Remove
it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 789471dba6fb30f15c752fbca46ddbefe5bfe850..4f3c0dac26b5576c69515a7c772e796c3ad860e0 100644 (file)
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -434,7 +434,6 @@ struct cgroup_subsys {
        void (*css_released)(struct cgroup_subsys_state *css);
        void (*css_free)(struct cgroup_subsys_state *css);
        void (*css_reset)(struct cgroup_subsys_state *css);
-       void (*css_e_css_changed)(struct cgroup_subsys_state *css);
 
        int (*can_attach)(struct cgroup_taskset *tset);
        void (*cancel_attach)(struct cgroup_taskset *tset);

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 68b032df77f55e76bb980c5af3adfc743af32574..7727b6e43e106a46556c12e3baa5e7a98c4fb87a 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3127,24 +3127,6 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
                }
        }
 
-       /*
-        * The effective csses of all the descendants (excluding @cgrp) may
-        * have changed.  Subsystems can optionally subscribe to this event
-        * by implementing ->css_e_css_changed() which is invoked if any of
-        * the effective csses seen from the css's cgroup may have changed.
-        */
-       for_each_subsys(ss, ssid) {
-               struct cgroup_subsys_state *this_css = cgroup_css(cgrp, ss);
-               struct cgroup_subsys_state *css;
-
-               if (!ss->css_e_css_changed || !this_css)
-                       continue;
-
-               css_for_each_descendant_pre(css, this_css)
-                       if (css != this_css)
-                               ss->css_e_css_changed(css);
-       }
-
        kernfs_activate(cgrp->kn);
        ret = 0;
 out_unlock: