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-rw-r--r--block/blk-cgroup.c27
1 files changed, 0 insertions, 27 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 582d2f18717e..d169e2055158 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1217,32 +1217,6 @@ void blkcg_exit_queue(struct request_queue *q)
blk_throtl_exit(q);
}
-/*
- * We cannot support shared io contexts, as we have no mean to support
- * two tasks with the same ioc in two different groups without major rework
- * of the main cic data structures. For now we allow a task to change
- * its cgroup only if it's the only owner of its ioc.
- */
-static int blkcg_can_attach(struct cgroup_taskset *tset)
-{
- struct task_struct *task;
- struct cgroup_subsys_state *dst_css;
- struct io_context *ioc;
- int ret = 0;
-
- /* task_lock() is needed to avoid races with exit_io_context() */
- cgroup_taskset_for_each(task, dst_css, tset) {
- task_lock(task);
- ioc = task->io_context;
- if (ioc && atomic_read(&ioc->nr_tasks) > 1)
- ret = -EINVAL;
- task_unlock(task);
- if (ret)
- break;
- }
- return ret;
-}
-
static void blkcg_bind(struct cgroup_subsys_state *root_css)
{
int i;
@@ -1275,7 +1249,6 @@ struct cgroup_subsys io_cgrp_subsys = {
.css_online = blkcg_css_online,
.css_offline = blkcg_css_offline,
.css_free = blkcg_css_free,
- .can_attach = blkcg_can_attach,
.css_rstat_flush = blkcg_rstat_flush,
.bind = blkcg_bind,
.dfl_cftypes = blkcg_files,