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cgroup: rename cgroup_subsys_state->dput_work and its callback function

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css (cgroup_subsys_state) will become RCU protected and there will be
two stages which require punting to work item during release.  To
prepare for using the work item for multiple times, rename
css->dput_work to css->destroy_work and css_dput_fn() to
css_free_work_fn() and move work item initialization from css init to
right before the actual usage.

This reorganization doesn't introduce any behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo 2013-08-13 11:01:54 -04:00
parent 40e93b39cd
commit 35ef10da65
2 changed files with 11 additions and 12 deletions
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2
include/linux/cgroup.h
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@ -80,7 +80,7 @@ struct cgroup_subsys_state {
struct css_id __rcu *id;
/* Used to put @cgroup->dentry on the last css_put() */
struct work_struct dput_work;
struct work_struct destroy_work;
};
/* bits in struct cgroup_subsys_state flags field */

21
kernel/cgroup.c
View File

@ -4259,10 +4259,10 @@ static int cgroup_populate_dir(struct cgroup *cgrp, unsigned long subsys_mask)
return ret;
}
static void css_dput_fn(struct work_struct *work)
static void css_free_work_fn(struct work_struct *work)
{
struct cgroup_subsys_state *css =
container_of(work, struct cgroup_subsys_state, dput_work);
container_of(work, struct cgroup_subsys_state, destroy_work);
cgroup_dput(css->cgroup);
}
@ -4272,7 +4272,14 @@ static void css_release(struct percpu_ref *ref)
struct cgroup_subsys_state *css =
container_of(ref, struct cgroup_subsys_state, refcnt);
schedule_work(&css->dput_work);
/*
* css holds an extra ref to @cgrp->dentry which is put on the last
* css_put(). dput() requires process context, which css_put() may
* be called without. @css->destroy_work will be used to invoke
* dput() asynchronously from css_put().
*/
INIT_WORK(&css->destroy_work, css_free_work_fn);
schedule_work(&css->destroy_work);
}
static void init_cgroup_css(struct cgroup_subsys_state *css,
@ -4287,14 +4294,6 @@ static void init_cgroup_css(struct cgroup_subsys_state *css,
css->flags |= CSS_ROOT;
BUG_ON(cgroup_css(cgrp, ss->subsys_id));
cgrp->subsys[ss->subsys_id] = css;
/*
* css holds an extra ref to @cgrp->dentry which is put on the last
* css_put(). dput() requires process context, which css_put() may
* be called without. @css->dput_work will be used to invoke
* dput() asynchronously from css_put().
*/
INIT_WORK(&css->dput_work, css_dput_fn);
}
/* invoke ->css_online() on a new CSS and mark it online if successful */