From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaohua Li Subject: Re: [PATCH] raid5: fix to detect failure of register_shrinker Date: Wed, 21 Sep 2016 09:01:10 -0700 Message-ID: <20160921160110.GA30281@kernel.org> References: <20160920023357.872-1-yuchao0@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20160920023357.872-1-yuchao0@huawei.com> Sender: linux-kernel-owner@vger.kernel.org To: Chao Yu Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, chao@kernel.org List-Id: linux-raid.ids On Tue, Sep 20, 2016 at 10:33:57AM +0800, Chao Yu wrote: > register_shrinker can fail after commit 1d3d4437eae1 ("vmscan: per-node > deferred work"), we should detect the failure of it, otherwise we may > fail to register shrinker after raid5 configuration was setup successfully. > > Signed-off-by: Chao Yu > --- > drivers/md/raid5.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c > index 766c3b7..b819a9a 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -6632,7 +6632,12 @@ static struct r5conf *setup_conf(struct mddev *mddev) > conf->shrinker.count_objects = raid5_cache_count; > conf->shrinker.batch = 128; > conf->shrinker.flags = 0; > - register_shrinker(&conf->shrinker); > + if (register_shrinker(&conf->shrinker)) { > + printk(KERN_ERR > + "md/raid:%s: couldn't register shrinker.\n", > + mdname(mddev)); > + goto abort; > + } > > sprintf(pers_name, "raid%d", mddev->new_level); > conf->thread = md_register_thread(raid5d, mddev, pers_name); shrinker isn't fatal for raid5. Idealy we can ignore the error and stop automatically stripe cache increase, but probable it's not worthy the effort. Applied the patch. Also the free_conf need better way to check if shrinker register successes. I add another patch to fix it. Thanks, Shaohua