From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + cgroup-css-id-support-remove-rcu_read_lock-from-css_get_next.patch added to -mm tree Date: Wed, 04 Mar 2009 13:47:05 -0800 Message-ID: <200903042147.n24Ll5Xi006321@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:37446 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754637AbZCDVrU (ORCPT ); Wed, 4 Mar 2009 16:47:20 -0500 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: bharata@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, dhaval@linux.vnet.ibm.com, kamezawa.hiroyu@jp.fujitsu.com, lizf@cn.fujitsu.com, menage@google.com The patch titled cgroup: remove rcu_read_lock() from css_get_next() has been added to the -mm tree. Its filename is cgroup-css-id-support-remove-rcu_read_lock-from-css_get_next.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: cgroup: remove rcu_read_lock() from css_get_next() From: Bharata B Rao Callers of css_get_next() are already calling css_get_next() under rcu_read_lock() and hence there there is no need for css_get_next() to re-acquire rcu_read_lock(). As per the comments in css_get_next(), let the callers accquire the rcu_read_lock(). Signed-off-by: Bharata B Rao Acked-by: KAMEZAWA Hiroyuki Cc: Balbir Singh Cc: Dhaval Giani Cc: Paul Menage Cc: Li Zefan Signed-off-by: Andrew Morton --- kernel/cgroup.c | 3 --- 1 file changed, 3 deletions(-) diff -puN kernel/cgroup.c~cgroup-css-id-support-remove-rcu_read_lock-from-css_get_next kernel/cgroup.c --- a/kernel/cgroup.c~cgroup-css-id-support-remove-rcu_read_lock-from-css_get_next +++ a/kernel/cgroup.c @@ -3500,7 +3500,6 @@ css_get_next(struct cgroup_subsys *ss, i return NULL; BUG_ON(!ss->use_id); - rcu_read_lock(); /* fill start point for scan */ tmpid = id; while (1) { @@ -3524,8 +3523,6 @@ css_get_next(struct cgroup_subsys *ss, i /* continue to scan from next id */ tmpid = tmpid + 1; }