From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Mandeep Singh Baines <msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: Li Zefan <lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Frederic Weisbecker
<fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
KAMEZAWA Hiroyuki
<kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>,
Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Paul Menage <paul-inf54ven1CmVyaH7bEyXVA@public.gmane.org>
Subject: Re: [PATCH 5/5] cgroup: separate out cgroup_attach_proc error handling code
Date: Tue, 20 Dec 2011 15:35:02 -0800 [thread overview]
Message-ID: <20111220233502.GN10752@google.com> (raw)
In-Reply-To: <1324422873-31001-6-git-send-email-msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Hello,
On Tue, Dec 20, 2011 at 03:14:33PM -0800, Mandeep Singh Baines wrote:
> @@ -2067,9 +2067,10 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
> read_unlock(&tasklist_lock);
>
> /* methods shouldn't be called if no task is actually migrating */
> - retval = 0;
> - if (!group_size)
> + if (!group_size) {
> + retval = 0;
> goto out_free_group_list;
> + }
Eh... I don't think this is an improvement. It's just different.
> @@ -2126,20 +2127,20 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
> */
> synchronize_rcu();
> cgroup_wakeup_rmdir_waiter(cgrp);
> - retval = 0;
> + flex_array_free(group);
> + return 0;
Hmm... maybe goto out_free_group_list? Duplicating cleanup on success
and failure paths can lead future updaters forget one of them. The
exit path in this function isn't pretty but I don't think the proposed
patch improves it either.
Thanks.
--
tejun
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: Mandeep Singh Baines <msb@chromium.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>,
LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Paul Menage <paul@paulmenage.org>
Subject: Re: [PATCH 5/5] cgroup: separate out cgroup_attach_proc error handling code
Date: Tue, 20 Dec 2011 15:35:02 -0800 [thread overview]
Message-ID: <20111220233502.GN10752@google.com> (raw)
In-Reply-To: <1324422873-31001-6-git-send-email-msb@chromium.org>
Hello,
On Tue, Dec 20, 2011 at 03:14:33PM -0800, Mandeep Singh Baines wrote:
> @@ -2067,9 +2067,10 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
> read_unlock(&tasklist_lock);
>
> /* methods shouldn't be called if no task is actually migrating */
> - retval = 0;
> - if (!group_size)
> + if (!group_size) {
> + retval = 0;
> goto out_free_group_list;
> + }
Eh... I don't think this is an improvement. It's just different.
> @@ -2126,20 +2127,20 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
> */
> synchronize_rcu();
> cgroup_wakeup_rmdir_waiter(cgrp);
> - retval = 0;
> + flex_array_free(group);
> + return 0;
Hmm... maybe goto out_free_group_list? Duplicating cleanup on success
and failure paths can lead future updaters forget one of them. The
exit path in this function isn't pretty but I don't think the proposed
patch improves it either.
Thanks.
--
tejun
next prev parent reply other threads:[~2011-12-20 23:35 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-20 23:14 [PATCH 0/5] cgroup: some cleanups of cgroup_attach_proc Mandeep Singh Baines
[not found] ` <1324422873-31001-1-git-send-email-msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2011-12-20 23:14 ` [PATCH 1/5 V3] cgroup: remove redundate get/put of old css_set from migrate Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
[not found] ` <1324422873-31001-2-git-send-email-msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2011-12-20 23:18 ` Tejun Heo
2011-12-20 23:18 ` Tejun Heo
[not found] ` <20111220231823.GK10752-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-20 23:41 ` Mandeep Singh Baines
2011-12-20 23:41 ` Mandeep Singh Baines
[not found] ` <20111220234131.GV13529-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-20 23:42 ` Tejun Heo
2011-12-20 23:42 ` Tejun Heo
[not found] ` <20111220234259.GO10752-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-20 23:46 ` Tejun Heo
2011-12-20 23:46 ` Tejun Heo
2011-12-20 23:46 ` Tejun Heo
2011-12-20 23:18 ` Tejun Heo
2011-12-21 1:10 ` Li Zefan
2011-12-21 1:10 ` Li Zefan
2011-12-21 1:10 ` Li Zefan
2011-12-20 23:14 ` [PATCH 2/5] cgroup: remove redundant get/put of task struct Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
[not found] ` <1324422873-31001-3-git-send-email-msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2011-12-20 23:23 ` Tejun Heo
2011-12-20 23:23 ` Tejun Heo
[not found] ` <20111220232326.GL10752-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-21 0:04 ` Mandeep Singh Baines
2011-12-21 0:04 ` Mandeep Singh Baines
2011-12-21 0:04 ` Mandeep Singh Baines
2011-12-20 23:14 ` [PATCH 3/5] cgroup: only need to check oldcgrp==newgrp once Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
[not found] ` <1324422873-31001-4-git-send-email-msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2011-12-21 1:29 ` Li Zefan
2011-12-21 1:29 ` Li Zefan
2011-12-20 23:14 ` [PATCH 4/5] cgroup: remove extra calls to find_existing_css_set Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
[not found] ` <1324422873-31001-5-git-send-email-msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2011-12-20 23:30 ` Tejun Heo
2011-12-20 23:30 ` Tejun Heo
[not found] ` <20111220233050.GM10752-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-20 23:47 ` Mandeep Singh Baines
2011-12-20 23:47 ` Mandeep Singh Baines
2011-12-20 23:47 ` Mandeep Singh Baines
2011-12-20 23:30 ` Tejun Heo
2011-12-20 23:14 ` [PATCH 5/5] cgroup: separate out cgroup_attach_proc error handling code Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
2011-12-20 23:14 ` Mandeep Singh Baines
[not found] ` <1324422873-31001-6-git-send-email-msb-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2011-12-20 23:35 ` Tejun Heo
2011-12-20 23:35 ` Tejun Heo [this message]
2011-12-20 23:35 ` Tejun Heo
[not found] ` <20111220233502.GN10752-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-21 0:02 ` Mandeep Singh Baines
2011-12-21 0:02 ` Mandeep Singh Baines
[not found] ` <20111221000231.GX13529-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2011-12-21 0:13 ` Tejun Heo
2011-12-21 0:13 ` Tejun Heo
2011-12-21 0:13 ` Tejun Heo
2011-12-21 0:02 ` Mandeep Singh Baines
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