From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756278Ab2ASBLz (ORCPT ); Wed, 18 Jan 2012 20:11:55 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:40268 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755274Ab2ASBLt (ORCPT ); Wed, 18 Jan 2012 20:11:49 -0500 From: Tejun Heo To: axboe@kernel.dk, vgoyal@redhat.com Cc: ctalbott@google.com, rni@google.com, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 07/12] blkcg: add blkio_policy[] array and allow one policy per policy ID Date: Wed, 18 Jan 2012 17:11:25 -0800 Message-Id: <1326935490-11827-8-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.7.7.3 In-Reply-To: <1326935490-11827-1-git-send-email-tj@kernel.org> References: <1326935490-11827-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Block cgroup policies are maintained in a linked list and, theoretically, multiple policies sharing the same policy ID are allowed. This patch temporarily restricts one policy per plid and adds blkio_policy[] array which indexes registered policy types by plid. Both the restriction and blkio_policy[] array are transitional and will be removed once API cleanup is complete. Signed-off-by: Tejun Heo Cc: Vivek Goyal --- block/blk-cgroup.c | 10 ++++++++++ block/blk-cgroup.h | 2 ++ 2 files changed, 12 insertions(+), 0 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 2babed7..940586b 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -28,6 +28,8 @@ static LIST_HEAD(blkio_list); struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; EXPORT_SYMBOL_GPL(blkio_root_cgroup); +static struct blkio_policy_type *blkio_policy[BLKIO_NR_POLICIES]; + static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, struct cgroup *); static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *, @@ -1665,7 +1667,11 @@ static void blkiocg_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, void blkio_policy_register(struct blkio_policy_type *blkiop) { spin_lock(&blkio_list_lock); + + BUG_ON(blkio_policy[blkiop->plid]); + blkio_policy[blkiop->plid] = blkiop; list_add_tail(&blkiop->list, &blkio_list); + spin_unlock(&blkio_list_lock); } EXPORT_SYMBOL_GPL(blkio_policy_register); @@ -1673,7 +1679,11 @@ EXPORT_SYMBOL_GPL(blkio_policy_register); void blkio_policy_unregister(struct blkio_policy_type *blkiop) { spin_lock(&blkio_list_lock); + + BUG_ON(blkio_policy[blkiop->plid] != blkiop); + blkio_policy[blkiop->plid] = NULL; list_del_init(&blkiop->list); + spin_unlock(&blkio_list_lock); } EXPORT_SYMBOL_GPL(blkio_policy_unregister); diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 599cc65..989d2f6 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -19,6 +19,8 @@ enum blkio_policy_id { BLKIO_POLICY_PROP = 0, /* Proportional Bandwidth division */ BLKIO_POLICY_THROTL, /* Throttling */ + + BLKIO_NR_POLICIES, }; /* Max limits for throttle policy */ -- 1.7.7.3