From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932288AbcELP00 (ORCPT ); Thu, 12 May 2016 11:26:26 -0400 Received: from mail-yw0-f193.google.com ([209.85.161.193]:35821 "EHLO mail-yw0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932096AbcELP0Y (ORCPT ); Thu, 12 May 2016 11:26:24 -0400 Date: Thu, 12 May 2016 11:10:45 -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 V4] block: add missing group association in bio-cloning functions Message-ID: <20160512151045.GR4775@htj.duckdns.org> References: <5732D47A.4090706@kyup.com> <1462958884-9457-1-git-send-email-paolo.valente@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1462958884-9457-1-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 Wed, May 11, 2016 at 11:28:04AM +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 > Reviewed-by: Nikolay Borisov Acked-by: Tejun Heo It prolly should also have the following tags Fixes: da2f0f74cf7d ("Btrfs: add support for blkio controllers") Cc: stable@vger.kernel.org # v4.3+ Thanks. -- tejun