From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752208AbcEJVDy (ORCPT ); Tue, 10 May 2016 17:03:54 -0400 Received: from mail-yw0-f193.google.com ([209.85.161.193]:36039 "EHLO mail-yw0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751227AbcEJVDw (ORCPT ); Tue, 10 May 2016 17:03:52 -0400 Date: Tue, 10 May 2016 17:03:50 -0400 From: Tejun Heo To: Paolo Valente Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, broonie@kernel.org, stable@vger.kernel.org Subject: Re: [PATCH BUGFIX V2] block: add missing group association in bio-cloning functions Message-ID: <20160510210350.GO7110@mtj.duckdns.org> References: <20160510204435.GN7110@mtj.duckdns.org> <1462914132-4479-1-git-send-email-paolo.valente@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1462914132-4479-1-git-send-email-paolo.valente@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 10, 2016 at 11:02:12PM +0200, Paolo Valente wrote: > When a bio is cloned, the newly created bio must be associated with > the same blkcg as the original bio (if BLK_CGROUP is enabled). If > this operation is not performed, then the new bio is not associated > with any group, and the group of the current task is returned when > the group of the bio is requested. > > Depending on the cloning frequency, this may cause a large > percentage of the bios belonging to a given group to be treated > as if belonging to other groups (in most cases as if belonging to > the root group). The expected group isolation may thereby be broken. > > This commit adds the missing association in bio-cloning functions. > > Signed-off-by: Paolo Valente Acked-by: Tejun Heo Thanks. -- tejun