From patchwork Fri May 6 20:45:12 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Valente X-Patchwork-Id: 9036311 Return-Path: X-Original-To: patchwork-linux-block@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id B5ABFBF29F for ; Fri, 6 May 2016 21:21:14 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id AE2A3203AC for ; Fri, 6 May 2016 21:21:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5689203A9 for ; Fri, 6 May 2016 21:21:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758397AbcEFVVM (ORCPT ); Fri, 6 May 2016 17:21:12 -0400 Received: from spostino.sms.unimo.it ([155.185.44.3]:60636 "EHLO spostino.sms.unimo.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756722AbcEFVVL (ORCPT ); Fri, 6 May 2016 17:21:11 -0400 X-Greylist: delayed 2125 seconds by postgrey-1.27 at vger.kernel.org; Fri, 06 May 2016 17:21:10 EDT Received: from [185.14.9.51] (port=50957 helo=localhost.localdomain) by spostino.sms.unimo.it with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA256:128) (Exim 4.80) (envelope-from ) id 1aymd1-0004cx-Pn; Fri, 06 May 2016 22:45:40 +0200 From: Paolo Valente To: Jens Axboe , Tejun Heo Cc: 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, Paolo Valente Subject: [PATCH BUGFIX] block: add missing group association in bio_split Date: Fri, 6 May 2016 22:45:12 +0200 Message-Id: <1462567512-3007-1-git-send-email-paolo.valente@linaro.org> X-Mailer: git-send-email 1.9.1 UNIMORE-X-SA-Score: -2.9 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Spam-Status: No, score=-9.0 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When a bio is split, 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 frequency of splits, 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 then broken. This commit adds the missing association in bio_split. Signed-off-by: Paolo Valente Acked-by: Tejun Heo --- block/bio.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/block/bio.c b/block/bio.c index 807d25e..c4a3834 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1811,6 +1811,11 @@ struct bio *bio_split(struct bio *bio, int sectors, bio_advance(bio, split->bi_iter.bi_size); +#ifdef CONFIG_BLK_CGROUP + if (bio->bi_css) + bio_associate_blkcg(split, bio->bi_css); +#endif + return split; } EXPORT_SYMBOL(bio_split);