Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757127Ab3G3Dj5 (ORCPT ); Mon, 29 Jul 2013 23:39:57 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:8878 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1757115Ab3G3Dje (ORCPT ); Mon, 29 Jul 2013 23:39:34 -0400 X-IronPort-AV: E=Sophos;i="4.89,774,1367942400"; d="scan'208";a="8064103" Message-ID: <51F735AE.2050902@cn.fujitsu.com> Date: Tue, 30 Jul 2013 11:40:30 +0800 From: Miao Xie Reply-To: miaox@cn.fujitsu.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Azat Khuzhin CC: linux-btrfs@vger.kernel.org, chris.mason@fusionio.com, open list Subject: Re: [PATCH] btrfs: use list_for_each_entry_safe() when delete items References: <1374919965-11690-1-git-send-email-a3at.mail@gmail.com> In-Reply-To: X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/07/30 11:37:17, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/07/30 11:37:18, Serialize complete at 2013/07/30 11:37:18 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1967 Lines: 61 On mon, 29 Jul 2013 11:48:32 +0400, Azat Khuzhin wrote: > On Sat, Jul 27, 2013 at 2:12 PM, Azat Khuzhin wrote: >> Replace list_for_each_entry() by list_for_each_entry_safe() in >> __btrfs_close_devices() >> >> There is another place that delete items lock_stripe_add(), but there we >> don't need safe version, because after deleting we exit from loop. >> >> Signed-off-by: Azat Khuzhin >> --- >> fs/btrfs/volumes.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >> index 78b8717..1d1b595 100644 >> --- a/fs/btrfs/volumes.c >> +++ b/fs/btrfs/volumes.c >> @@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head) >> >> static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices) >> { >> - struct btrfs_device *device; >> + struct btrfs_device *device, *next; >> >> if (--fs_devices->opened > 0) >> return 0; >> >> mutex_lock(&fs_devices->device_list_mutex); >> - list_for_each_entry(device, &fs_devices->devices, dev_list) { >> + list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) { >> struct btrfs_device *new_device; >> struct rcu_string *name; > > There is "kfree(device);" at the end of loop, maybe there must "goto > again;" after it? > (instead of this patch) Your fix is right, we needn't search from the head once again. The other fix way is: call_rcu(&device->rcu, free_device); + device = new_device; } but from the viewpoint of the readability, this way is not so good. Reviewed-by: Miao Xie > >> >> -- >> 1.7.10.4 >> > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/