From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 02/14] cgroup: rename cgroup_subsys_state->dput_work and its callback function Date: Thu, 8 Aug 2013 16:13:39 -0400 Message-ID: <1375992831-4650-3-git-send-email-tj@kernel.org> References: <1375992831-4650-1-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1375992831-4650-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org Cc: Tejun Heo , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: containers.vger.kernel.org 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 --- 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