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 <t...@kernel.org>
---
include/linux/cgroup.h | 2 +-
kernel/cgroup.c | 21 ++++++++++-----------
2 files changed, 11 insertions(+), 12 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 8ec5b0f..12d66fe 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -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 */
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 49ad96e..0b28097 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4259,10 +4259,10 @@ err:
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 */
--
1.8.3.1
--
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