From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f45.google.com (mail-qg0-f45.google.com [209.85.192.45]) by kanga.kvack.org (Postfix) with ESMTP id 884E66B00EF for ; Tue, 6 Jan 2015 14:29:30 -0500 (EST) Received: by mail-qg0-f45.google.com with SMTP id z107so6115281qgd.18 for ; Tue, 06 Jan 2015 11:29:30 -0800 (PST) Received: from mail-qc0-x22f.google.com (mail-qc0-x22f.google.com. [2607:f8b0:400d:c01::22f]) by mx.google.com with ESMTPS id l78si8660490qgd.65.2015.01.06.11.29.26 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 06 Jan 2015 11:29:27 -0800 (PST) Received: by mail-qc0-f175.google.com with SMTP id p6so1311312qcv.34 for ; Tue, 06 Jan 2015 11:29:26 -0800 (PST) From: Tejun Heo Subject: [PATCH 03/16] blkcg: add blkcg_root_css Date: Tue, 6 Jan 2015 14:29:04 -0500 Message-Id: <1420572557-11572-4-git-send-email-tj@kernel.org> In-Reply-To: <1420572557-11572-1-git-send-email-tj@kernel.org> References: <1420572557-11572-1-git-send-email-tj@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, Tejun Heo cgroup writeback support would need to tell whether a given blkcg cgroup_subsys_state is the root one or not. Add global constant blkcg_root_css which points to &blkcg_root.css. If blkcg is disabled, it's defined as ERR_PTR(-EINVAL). v2: The declarations moved to include/linux/blk-cgroup.h as suggested by Vivek. Signed-off-by: Tejun Heo Cc: Vivek Goyal Cc: Jens Axboe --- block/blk-cgroup.c | 2 ++ include/linux/blk-cgroup.h | 3 +++ 2 files changed, 5 insertions(+) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c3226ce..9e0fe38 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -30,6 +30,8 @@ struct blkcg blkcg_root = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT, .cfq_leaf_weight = 2 * CFQ_WEIGHT_DEFAULT, }; EXPORT_SYMBOL_GPL(blkcg_root); +struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css; + static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS]; static bool blkcg_policy_enabled(struct request_queue *q, diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 51f95b3..65f0c17 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -134,6 +134,7 @@ struct blkcg_policy { }; extern struct blkcg blkcg_root; +extern struct cgroup_subsys_state * const blkcg_root_css; struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q); struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, @@ -570,6 +571,8 @@ struct blkcg_gq { struct blkcg_policy { }; +#define blkcg_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL)) + #ifdef CONFIG_BLOCK static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } -- 2.1.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org