cgroup: remove bind() method from cgroup_subsys.

The bind() method of cgroup_subsys is not used in any of the
controllers (cpuset, freezer, blkio, net_cls, memcg, net_prio,
devices, perf, hugetlb, cpu and cpuacct)

tj: Removed the entry on ->bind() from
    Documentation/cgroups/cgroups.txt.  Also updated a couple
    paragraphs which were suggesting that dynamic re-binding may be
    implemented.  It's not gonna.

Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 0 insertions, 4 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index ba3e24a76dae..fd38e1cfacca 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1064,16 +1064,12 @@ static int rebind_subsystems(struct cgroupfs_root *root,
                         cgrp->subsys[i]->cgroup = cgrp;
                         list_move(&ss->sibling, &root->subsys_list);
                         ss->root = root;
-                        if (ss->bind)
-                                ss->bind(cgrp);
                         /* refcount was already taken, and we're keeping it */
                 } else if (bit & removed_mask) {
                         /* We're removing this subsystem */
                         BUG_ON(ss == NULL);
                         BUG_ON(cgrp->subsys[i] != dummytop->subsys[i]);
                         BUG_ON(cgrp->subsys[i]->cgroup != cgrp);
-                        if (ss->bind)
-                                ss->bind(dummytop);
                         dummytop->subsys[i]->cgroup = dummytop;
                         cgrp->subsys[i] = NULL;
                         subsys[i]->root = &rootnode;